diff --git a/1000-hours/.vitepress/config.mts b/1000-hours/.vitepress/config.mts
index a56c5621..49f2fb05 100644
--- a/1000-hours/.vitepress/config.mts
+++ b/1000-hours/.vitepress/config.mts
@@ -237,22 +237,11 @@ export default withMermaid(
               },
               {
                 text: "5. 基础之上",
-                collapsed: true,
                 link: "/sounds-of-american-english/5-above-ground",
-                items: [
-                  {
-                    text: "5.1. 流利",
-                    link: "/sounds-of-american-english/5.1-fluency",
-                  },
-                  {
-                    text: "5.2. 情绪",
-                    link: "/sounds-of-american-english/5.2-emotions",
-                  },
-                ],
               },
               {
-                text: "6. 而后",
-                link: "/sounds-of-american-english/5-sumup",
+                text: "6. 词汇构建",
+                link: "/sounds-of-american-english/6-vocabulary",
               },
             ],
           },
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diff --git a/1000-hours/public/audios/transport-us-female.mp3 b/1000-hours/public/audios/transport-us-female.mp3
new file mode 100644
index 00000000..6441a0a4
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diff --git a/1000-hours/public/audios/transport-us-male.mp3 b/1000-hours/public/audios/transport-us-male.mp3
new file mode 100644
index 00000000..3e2b22e8
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diff --git a/1000-hours/public/audios/typewriter-us-female.mp3 b/1000-hours/public/audios/typewriter-us-female.mp3
new file mode 100644
index 00000000..ced75622
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diff --git a/1000-hours/public/audios/typewriter-us-male.mp3 b/1000-hours/public/audios/typewriter-us-male.mp3
new file mode 100644
index 00000000..1299c878
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diff --git a/1000-hours/public/audios/underestimate-us-female.mp3 b/1000-hours/public/audios/underestimate-us-female.mp3
new file mode 100644
index 00000000..fbf2d6e8
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diff --git a/1000-hours/public/audios/underestimate-us-male.mp3 b/1000-hours/public/audios/underestimate-us-male.mp3
new file mode 100644
index 00000000..8248184d
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diff --git a/1000-hours/public/audios/underground-us-female.mp3 b/1000-hours/public/audios/underground-us-female.mp3
new file mode 100644
index 00000000..485bb048
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diff --git a/1000-hours/public/audios/underground-us-male.mp3 b/1000-hours/public/audios/underground-us-male.mp3
new file mode 100644
index 00000000..c9de2128
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diff --git a/1000-hours/public/audios/underpaid-us-female.mp3 b/1000-hours/public/audios/underpaid-us-female.mp3
new file mode 100644
index 00000000..e87484f6
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diff --git a/1000-hours/public/audios/underpaid-us-male.mp3 b/1000-hours/public/audios/underpaid-us-male.mp3
new file mode 100644
index 00000000..42b9986f
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diff --git a/1000-hours/public/audios/underwater-us-female.mp3 b/1000-hours/public/audios/underwater-us-female.mp3
new file mode 100644
index 00000000..d91a3cd2
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diff --git a/1000-hours/public/audios/underwater-us-male.mp3 b/1000-hours/public/audios/underwater-us-male.mp3
new file mode 100644
index 00000000..1e95d896
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diff --git a/1000-hours/public/audios/unhappy-us-female.mp3 b/1000-hours/public/audios/unhappy-us-female.mp3
new file mode 100644
index 00000000..3c36cae7
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diff --git a/1000-hours/public/audios/unhappy-us-male.mp3 b/1000-hours/public/audios/unhappy-us-male.mp3
new file mode 100644
index 00000000..6e6496e7
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diff --git a/1000-hours/public/audios/unknown-us-female.mp3 b/1000-hours/public/audios/unknown-us-female.mp3
new file mode 100644
index 00000000..e38b8725
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diff --git a/1000-hours/public/audios/unknown-us-male.mp3 b/1000-hours/public/audios/unknown-us-male.mp3
new file mode 100644
index 00000000..0855cbfa
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diff --git a/1000-hours/public/audios/unusual-us-female.mp3 b/1000-hours/public/audios/unusual-us-female.mp3
new file mode 100644
index 00000000..61242087
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diff --git a/1000-hours/public/audios/unusual-us-male.mp3 b/1000-hours/public/audios/unusual-us-male.mp3
new file mode 100644
index 00000000..4ac63f70
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diff --git a/1000-hours/public/audios/upstairs-us-female.mp3 b/1000-hours/public/audios/upstairs-us-female.mp3
new file mode 100644
index 00000000..2d2911da
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diff --git a/1000-hours/public/audios/upstairs-us-male.mp3 b/1000-hours/public/audios/upstairs-us-male.mp3
new file mode 100644
index 00000000..0c5b06cf
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diff --git a/1000-hours/public/audios/vacant-us-female.mp3 b/1000-hours/public/audios/vacant-us-female.mp3
new file mode 100644
index 00000000..972a2655
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diff --git a/1000-hours/public/audios/vacant-us-male.mp3 b/1000-hours/public/audios/vacant-us-male.mp3
new file mode 100644
index 00000000..0d16667b
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diff --git a/1000-hours/public/audios/vacuum-us-female.mp3 b/1000-hours/public/audios/vacuum-us-female.mp3
new file mode 100644
index 00000000..516e1739
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diff --git a/1000-hours/public/audios/vacuum-us-male.mp3 b/1000-hours/public/audios/vacuum-us-male.mp3
new file mode 100644
index 00000000..51c540e5
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diff --git a/1000-hours/public/audios/video-us-female.mp3 b/1000-hours/public/audios/video-us-female.mp3
new file mode 100644
index 00000000..6885ab3e
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diff --git a/1000-hours/public/audios/video-us-male.mp3 b/1000-hours/public/audios/video-us-male.mp3
new file mode 100644
index 00000000..835e36e5
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diff --git a/1000-hours/public/audios/visible-us-female.mp3 b/1000-hours/public/audios/visible-us-female.mp3
new file mode 100644
index 00000000..eecc3f09
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diff --git a/1000-hours/public/audios/visible-us-male.mp3 b/1000-hours/public/audios/visible-us-male.mp3
new file mode 100644
index 00000000..96606b5f
Binary files /dev/null and b/1000-hours/public/audios/visible-us-male.mp3 differ
diff --git a/1000-hours/public/audios/volleyball-us-female.mp3 b/1000-hours/public/audios/volleyball-us-female.mp3
new file mode 100644
index 00000000..7f91d86c
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diff --git a/1000-hours/public/audios/volleyball-us-male.mp3 b/1000-hours/public/audios/volleyball-us-male.mp3
new file mode 100644
index 00000000..7228328c
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diff --git a/1000-hours/public/audios/waterfall-us-female.mp3 b/1000-hours/public/audios/waterfall-us-female.mp3
new file mode 100644
index 00000000..f9be2bf0
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diff --git a/1000-hours/public/audios/waterfall-us-male.mp3 b/1000-hours/public/audios/waterfall-us-male.mp3
new file mode 100644
index 00000000..94c0cbd7
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diff --git a/1000-hours/public/audios/watermelon-us-female.mp3 b/1000-hours/public/audios/watermelon-us-female.mp3
new file mode 100644
index 00000000..cfe613d5
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diff --git a/1000-hours/public/audios/watermelon-us-male.mp3 b/1000-hours/public/audios/watermelon-us-male.mp3
new file mode 100644
index 00000000..2791a5c5
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diff --git a/1000-hours/public/audios/weekend-us-female.mp3 b/1000-hours/public/audios/weekend-us-female.mp3
new file mode 100644
index 00000000..815dd7e1
Binary files /dev/null and b/1000-hours/public/audios/weekend-us-female.mp3 differ
diff --git a/1000-hours/public/audios/weekend-us-male.mp3 b/1000-hours/public/audios/weekend-us-male.mp3
new file mode 100644
index 00000000..42202f50
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diff --git a/1000-hours/public/audios/wheelchair-us-female.mp3 b/1000-hours/public/audios/wheelchair-us-female.mp3
new file mode 100644
index 00000000..82a09fc5
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diff --git a/1000-hours/public/audios/wheelchair-us-male.mp3 b/1000-hours/public/audios/wheelchair-us-male.mp3
new file mode 100644
index 00000000..a1bba2cd
Binary files /dev/null and b/1000-hours/public/audios/wheelchair-us-male.mp3 differ
diff --git a/1000-hours/public/audios/windmill-us-female.mp3 b/1000-hours/public/audios/windmill-us-female.mp3
new file mode 100644
index 00000000..64c2e3b9
Binary files /dev/null and b/1000-hours/public/audios/windmill-us-female.mp3 differ
diff --git a/1000-hours/public/audios/windmill-us-male.mp3 b/1000-hours/public/audios/windmill-us-male.mp3
new file mode 100644
index 00000000..62ea8ed9
Binary files /dev/null and b/1000-hours/public/audios/windmill-us-male.mp3 differ
diff --git a/1000-hours/public/audios/workshop-us-female.mp3 b/1000-hours/public/audios/workshop-us-female.mp3
new file mode 100644
index 00000000..83c71f1d
Binary files /dev/null and b/1000-hours/public/audios/workshop-us-female.mp3 differ
diff --git a/1000-hours/public/audios/workshop-us-male.mp3 b/1000-hours/public/audios/workshop-us-male.mp3
new file mode 100644
index 00000000..8a10e3aa
Binary files /dev/null and b/1000-hours/public/audios/workshop-us-male.mp3 differ
diff --git a/1000-hours/public/jupyter-notebooks/edge-tts-valcab-pronounciation.ipynb b/1000-hours/public/jupyter-notebooks/edge-tts-valcab-pronounciation.ipynb
index 211e3b77..0a9ca3af 100644
--- a/1000-hours/public/jupyter-notebooks/edge-tts-valcab-pronounciation.ipynb
+++ b/1000-hours/public/jupyter-notebooks/edge-tts-valcab-pronounciation.ipynb
@@ -64,7 +64,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 20,
+   "execution_count": 56,
    "id": "4146f92e",
    "metadata": {},
    "outputs": [
@@ -73,9 +73,9 @@
      "output_type": "stream",
      "text": [
       "['en-US-GuyNeural', 'en-US-AriaNeural']\n",
-      "network\n",
-      "../audios/network-us-male.mp3 created\n",
-      "../audios/network-us-female.mp3 created\n"
+      "are\n",
+      "../audios/are-us-male.mp3 created\n",
+      "../audios/are-us-female.mp3 created\n"
      ]
     }
    ],
@@ -92,7 +92,7 @@
     "    print(voices)\n",
     "\n",
     "words = \"\"\"\n",
-    "network\n",
+    "are\n",
     "\"\"\"\n",
     "\n",
     "for word in words.strip().split(','):\n",
@@ -263,7 +263,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 38,
+   "execution_count": 55,
    "id": "7350bdce",
    "metadata": {},
    "outputs": [
@@ -271,21 +271,58 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "../audios/ten-cups-us-alloy.mp3\n",
-      "../audios/ten-cups-us-female.mp3\n",
-      "../audios/increase-us-alloy.mp3\n",
-      "../audios/increase-us-female.mp3\n",
-      "../audios/brown-gate-us-alloy.mp3\n",
-      "../audios/brown-gate-us-female.mp3\n"
+      "../audios/are-us-male.mp3\n"
+     ]
+    },
+    {
+     "ename": "APIConnectionError",
+     "evalue": "Connection error.",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+      "\u001b[0;31mConnectError\u001b[0m                              Traceback (most recent call last)",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/httpx/_transports/default.py:69\u001b[0m, in \u001b[0;36mmap_httpcore_exceptions\u001b[0;34m()\u001b[0m\n\u001b[1;32m     68\u001b[0m \u001b[38;5;28;01mtry\u001b[39;00m:\n\u001b[0;32m---> 69\u001b[0m     \u001b[38;5;28;01myield\u001b[39;00m\n\u001b[1;32m     70\u001b[0m \u001b[38;5;28;01mexcept\u001b[39;00m \u001b[38;5;167;01mException\u001b[39;00m \u001b[38;5;28;01mas\u001b[39;00m exc:\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/httpx/_transports/default.py:233\u001b[0m, in \u001b[0;36mHTTPTransport.handle_request\u001b[0;34m(self, request)\u001b[0m\n\u001b[1;32m    232\u001b[0m \u001b[38;5;28;01mwith\u001b[39;00m map_httpcore_exceptions():\n\u001b[0;32m--> 233\u001b[0m     resp \u001b[38;5;241m=\u001b[39m \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43m_pool\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mhandle_request\u001b[49m\u001b[43m(\u001b[49m\u001b[43mreq\u001b[49m\u001b[43m)\u001b[49m\n\u001b[1;32m    235\u001b[0m \u001b[38;5;28;01massert\u001b[39;00m \u001b[38;5;28misinstance\u001b[39m(resp\u001b[38;5;241m.\u001b[39mstream, typing\u001b[38;5;241m.\u001b[39mIterable)\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/httpcore/_sync/connection_pool.py:216\u001b[0m, in \u001b[0;36mConnectionPool.handle_request\u001b[0;34m(self, request)\u001b[0m\n\u001b[1;32m    215\u001b[0m     \u001b[38;5;28mself\u001b[39m\u001b[38;5;241m.\u001b[39m_close_connections(closing)\n\u001b[0;32m--> 216\u001b[0m     \u001b[38;5;28;01mraise\u001b[39;00m exc \u001b[38;5;28;01mfrom\u001b[39;00m \u001b[38;5;28;01mNone\u001b[39;00m\n\u001b[1;32m    218\u001b[0m \u001b[38;5;66;03m# Return the response. Note that in this case we still have to manage\u001b[39;00m\n\u001b[1;32m    219\u001b[0m \u001b[38;5;66;03m# the point at which the response is closed.\u001b[39;00m\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/httpcore/_sync/connection_pool.py:196\u001b[0m, in \u001b[0;36mConnectionPool.handle_request\u001b[0;34m(self, request)\u001b[0m\n\u001b[1;32m    194\u001b[0m \u001b[38;5;28;01mtry\u001b[39;00m:\n\u001b[1;32m    195\u001b[0m     \u001b[38;5;66;03m# Send the request on the assigned connection.\u001b[39;00m\n\u001b[0;32m--> 196\u001b[0m     response \u001b[38;5;241m=\u001b[39m \u001b[43mconnection\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mhandle_request\u001b[49m\u001b[43m(\u001b[49m\n\u001b[1;32m    197\u001b[0m \u001b[43m        \u001b[49m\u001b[43mpool_request\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mrequest\u001b[49m\n\u001b[1;32m    198\u001b[0m \u001b[43m    \u001b[49m\u001b[43m)\u001b[49m\n\u001b[1;32m    199\u001b[0m \u001b[38;5;28;01mexcept\u001b[39;00m ConnectionNotAvailable:\n\u001b[1;32m    200\u001b[0m     \u001b[38;5;66;03m# In some cases a connection may initially be available to\u001b[39;00m\n\u001b[1;32m    201\u001b[0m     \u001b[38;5;66;03m# handle a request, but then become unavailable.\u001b[39;00m\n\u001b[1;32m    202\u001b[0m     \u001b[38;5;66;03m#\u001b[39;00m\n\u001b[1;32m    203\u001b[0m     \u001b[38;5;66;03m# In this case we clear the connection and try again.\u001b[39;00m\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/httpcore/_sync/http_proxy.py:317\u001b[0m, in \u001b[0;36mTunnelHTTPConnection.handle_request\u001b[0;34m(self, request)\u001b[0m\n\u001b[1;32m    316\u001b[0m \u001b[38;5;28;01mwith\u001b[39;00m Trace(\u001b[38;5;124m\"\u001b[39m\u001b[38;5;124mstart_tls\u001b[39m\u001b[38;5;124m\"\u001b[39m, logger, request, kwargs) \u001b[38;5;28;01mas\u001b[39;00m trace:\n\u001b[0;32m--> 317\u001b[0m     stream \u001b[38;5;241m=\u001b[39m \u001b[43mstream\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mstart_tls\u001b[49m\u001b[43m(\u001b[49m\u001b[38;5;241;43m*\u001b[39;49m\u001b[38;5;241;43m*\u001b[39;49m\u001b[43mkwargs\u001b[49m\u001b[43m)\u001b[49m\n\u001b[1;32m    318\u001b[0m     trace\u001b[38;5;241m.\u001b[39mreturn_value \u001b[38;5;241m=\u001b[39m stream\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/httpcore/_sync/http11.py:383\u001b[0m, in \u001b[0;36mHTTP11UpgradeStream.start_tls\u001b[0;34m(self, ssl_context, server_hostname, timeout)\u001b[0m\n\u001b[1;32m    377\u001b[0m \u001b[38;5;28;01mdef\u001b[39;00m \u001b[38;5;21mstart_tls\u001b[39m(\n\u001b[1;32m    378\u001b[0m     \u001b[38;5;28mself\u001b[39m,\n\u001b[1;32m    379\u001b[0m     ssl_context: ssl\u001b[38;5;241m.\u001b[39mSSLContext,\n\u001b[1;32m    380\u001b[0m     server_hostname: Optional[\u001b[38;5;28mstr\u001b[39m] \u001b[38;5;241m=\u001b[39m \u001b[38;5;28;01mNone\u001b[39;00m,\n\u001b[1;32m    381\u001b[0m     timeout: Optional[\u001b[38;5;28mfloat\u001b[39m] \u001b[38;5;241m=\u001b[39m \u001b[38;5;28;01mNone\u001b[39;00m,\n\u001b[1;32m    382\u001b[0m ) \u001b[38;5;241m-\u001b[39m\u001b[38;5;241m>\u001b[39m NetworkStream:\n\u001b[0;32m--> 383\u001b[0m     \u001b[38;5;28;01mreturn\u001b[39;00m \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43m_stream\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mstart_tls\u001b[49m\u001b[43m(\u001b[49m\u001b[43mssl_context\u001b[49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[43mserver_hostname\u001b[49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[43mtimeout\u001b[49m\u001b[43m)\u001b[49m\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/httpcore/_backends/sync.py:152\u001b[0m, in \u001b[0;36mSyncStream.start_tls\u001b[0;34m(self, ssl_context, server_hostname, timeout)\u001b[0m\n\u001b[1;32m    148\u001b[0m exc_map: ExceptionMapping \u001b[38;5;241m=\u001b[39m {\n\u001b[1;32m    149\u001b[0m     socket\u001b[38;5;241m.\u001b[39mtimeout: ConnectTimeout,\n\u001b[1;32m    150\u001b[0m     \u001b[38;5;167;01mOSError\u001b[39;00m: ConnectError,\n\u001b[1;32m    151\u001b[0m }\n\u001b[0;32m--> 152\u001b[0m \u001b[43m\u001b[49m\u001b[38;5;28;43;01mwith\u001b[39;49;00m\u001b[43m \u001b[49m\u001b[43mmap_exceptions\u001b[49m\u001b[43m(\u001b[49m\u001b[43mexc_map\u001b[49m\u001b[43m)\u001b[49m\u001b[43m:\u001b[49m\n\u001b[1;32m    153\u001b[0m \u001b[43m    \u001b[49m\u001b[38;5;28;43;01mtry\u001b[39;49;00m\u001b[43m:\u001b[49m\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/contextlib.py:158\u001b[0m, in \u001b[0;36m_GeneratorContextManager.__exit__\u001b[0;34m(self, typ, value, traceback)\u001b[0m\n\u001b[1;32m    157\u001b[0m \u001b[38;5;28;01mtry\u001b[39;00m:\n\u001b[0;32m--> 158\u001b[0m     \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mgen\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mthrow\u001b[49m\u001b[43m(\u001b[49m\u001b[43mvalue\u001b[49m\u001b[43m)\u001b[49m\n\u001b[1;32m    159\u001b[0m \u001b[38;5;28;01mexcept\u001b[39;00m \u001b[38;5;167;01mStopIteration\u001b[39;00m \u001b[38;5;28;01mas\u001b[39;00m exc:\n\u001b[1;32m    160\u001b[0m     \u001b[38;5;66;03m# Suppress StopIteration *unless* it's the same exception that\u001b[39;00m\n\u001b[1;32m    161\u001b[0m     \u001b[38;5;66;03m# was passed to throw().  This prevents a StopIteration\u001b[39;00m\n\u001b[1;32m    162\u001b[0m     \u001b[38;5;66;03m# raised inside the \"with\" statement from being suppressed.\u001b[39;00m\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/httpcore/_exceptions.py:14\u001b[0m, in \u001b[0;36mmap_exceptions\u001b[0;34m(map)\u001b[0m\n\u001b[1;32m     13\u001b[0m     \u001b[38;5;28;01mif\u001b[39;00m \u001b[38;5;28misinstance\u001b[39m(exc, from_exc):\n\u001b[0;32m---> 14\u001b[0m         \u001b[38;5;28;01mraise\u001b[39;00m to_exc(exc) \u001b[38;5;28;01mfrom\u001b[39;00m \u001b[38;5;21;01mexc\u001b[39;00m\n\u001b[1;32m     15\u001b[0m \u001b[38;5;28;01mraise\u001b[39;00m\n",
+      "\u001b[0;31mConnectError\u001b[0m: [SSL: UNEXPECTED_EOF_WHILE_READING] EOF occurred in violation of protocol (_ssl.c:1000)",
+      "\nThe above exception was the direct cause of the following exception:\n",
+      "\u001b[0;31mConnectError\u001b[0m                              Traceback (most recent call last)",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/openai/_base_client.py:978\u001b[0m, in \u001b[0;36mSyncAPIClient._request\u001b[0;34m(self, cast_to, options, remaining_retries, stream, stream_cls)\u001b[0m\n\u001b[1;32m    977\u001b[0m \u001b[38;5;28;01mtry\u001b[39;00m:\n\u001b[0;32m--> 978\u001b[0m     response \u001b[38;5;241m=\u001b[39m \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43m_client\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43msend\u001b[49m\u001b[43m(\u001b[49m\n\u001b[1;32m    979\u001b[0m \u001b[43m        \u001b[49m\u001b[43mrequest\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    980\u001b[0m \u001b[43m        \u001b[49m\u001b[43mstream\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mstream\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;129;43;01mor\u001b[39;49;00m\u001b[43m \u001b[49m\u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43m_should_stream_response_body\u001b[49m\u001b[43m(\u001b[49m\u001b[43mrequest\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mrequest\u001b[49m\u001b[43m)\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    981\u001b[0m \u001b[43m        \u001b[49m\u001b[38;5;241;43m*\u001b[39;49m\u001b[38;5;241;43m*\u001b[39;49m\u001b[43mkwargs\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    982\u001b[0m \u001b[43m    \u001b[49m\u001b[43m)\u001b[49m\n\u001b[1;32m    983\u001b[0m \u001b[38;5;28;01mexcept\u001b[39;00m httpx\u001b[38;5;241m.\u001b[39mTimeoutException \u001b[38;5;28;01mas\u001b[39;00m err:\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/httpx/_client.py:914\u001b[0m, in \u001b[0;36mClient.send\u001b[0;34m(self, request, stream, auth, follow_redirects)\u001b[0m\n\u001b[1;32m    912\u001b[0m auth \u001b[38;5;241m=\u001b[39m \u001b[38;5;28mself\u001b[39m\u001b[38;5;241m.\u001b[39m_build_request_auth(request, auth)\n\u001b[0;32m--> 914\u001b[0m response \u001b[38;5;241m=\u001b[39m \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43m_send_handling_auth\u001b[49m\u001b[43m(\u001b[49m\n\u001b[1;32m    915\u001b[0m \u001b[43m    \u001b[49m\u001b[43mrequest\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    916\u001b[0m \u001b[43m    \u001b[49m\u001b[43mauth\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mauth\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    917\u001b[0m \u001b[43m    \u001b[49m\u001b[43mfollow_redirects\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mfollow_redirects\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    918\u001b[0m \u001b[43m    \u001b[49m\u001b[43mhistory\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43m[\u001b[49m\u001b[43m]\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    919\u001b[0m \u001b[43m\u001b[49m\u001b[43m)\u001b[49m\n\u001b[1;32m    920\u001b[0m \u001b[38;5;28;01mtry\u001b[39;00m:\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/httpx/_client.py:942\u001b[0m, in \u001b[0;36mClient._send_handling_auth\u001b[0;34m(self, request, auth, follow_redirects, history)\u001b[0m\n\u001b[1;32m    941\u001b[0m \u001b[38;5;28;01mwhile\u001b[39;00m \u001b[38;5;28;01mTrue\u001b[39;00m:\n\u001b[0;32m--> 942\u001b[0m     response \u001b[38;5;241m=\u001b[39m \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43m_send_handling_redirects\u001b[49m\u001b[43m(\u001b[49m\n\u001b[1;32m    943\u001b[0m \u001b[43m        \u001b[49m\u001b[43mrequest\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    944\u001b[0m \u001b[43m        \u001b[49m\u001b[43mfollow_redirects\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mfollow_redirects\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    945\u001b[0m \u001b[43m        \u001b[49m\u001b[43mhistory\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mhistory\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    946\u001b[0m \u001b[43m    \u001b[49m\u001b[43m)\u001b[49m\n\u001b[1;32m    947\u001b[0m     \u001b[38;5;28;01mtry\u001b[39;00m:\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/httpx/_client.py:979\u001b[0m, in \u001b[0;36mClient._send_handling_redirects\u001b[0;34m(self, request, follow_redirects, history)\u001b[0m\n\u001b[1;32m    977\u001b[0m     hook(request)\n\u001b[0;32m--> 979\u001b[0m response \u001b[38;5;241m=\u001b[39m \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43m_send_single_request\u001b[49m\u001b[43m(\u001b[49m\u001b[43mrequest\u001b[49m\u001b[43m)\u001b[49m\n\u001b[1;32m    980\u001b[0m \u001b[38;5;28;01mtry\u001b[39;00m:\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/httpx/_client.py:1015\u001b[0m, in \u001b[0;36mClient._send_single_request\u001b[0;34m(self, request)\u001b[0m\n\u001b[1;32m   1014\u001b[0m \u001b[38;5;28;01mwith\u001b[39;00m request_context(request\u001b[38;5;241m=\u001b[39mrequest):\n\u001b[0;32m-> 1015\u001b[0m     response \u001b[38;5;241m=\u001b[39m \u001b[43mtransport\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mhandle_request\u001b[49m\u001b[43m(\u001b[49m\u001b[43mrequest\u001b[49m\u001b[43m)\u001b[49m\n\u001b[1;32m   1017\u001b[0m \u001b[38;5;28;01massert\u001b[39;00m \u001b[38;5;28misinstance\u001b[39m(response\u001b[38;5;241m.\u001b[39mstream, SyncByteStream)\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/httpx/_transports/default.py:232\u001b[0m, in \u001b[0;36mHTTPTransport.handle_request\u001b[0;34m(self, request)\u001b[0m\n\u001b[1;32m    220\u001b[0m req \u001b[38;5;241m=\u001b[39m httpcore\u001b[38;5;241m.\u001b[39mRequest(\n\u001b[1;32m    221\u001b[0m     method\u001b[38;5;241m=\u001b[39mrequest\u001b[38;5;241m.\u001b[39mmethod,\n\u001b[1;32m    222\u001b[0m     url\u001b[38;5;241m=\u001b[39mhttpcore\u001b[38;5;241m.\u001b[39mURL(\n\u001b[0;32m   (...)\u001b[0m\n\u001b[1;32m    230\u001b[0m     extensions\u001b[38;5;241m=\u001b[39mrequest\u001b[38;5;241m.\u001b[39mextensions,\n\u001b[1;32m    231\u001b[0m )\n\u001b[0;32m--> 232\u001b[0m \u001b[43m\u001b[49m\u001b[38;5;28;43;01mwith\u001b[39;49;00m\u001b[43m \u001b[49m\u001b[43mmap_httpcore_exceptions\u001b[49m\u001b[43m(\u001b[49m\u001b[43m)\u001b[49m\u001b[43m:\u001b[49m\n\u001b[1;32m    233\u001b[0m \u001b[43m    \u001b[49m\u001b[43mresp\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43m \u001b[49m\u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43m_pool\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mhandle_request\u001b[49m\u001b[43m(\u001b[49m\u001b[43mreq\u001b[49m\u001b[43m)\u001b[49m\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/contextlib.py:158\u001b[0m, in \u001b[0;36m_GeneratorContextManager.__exit__\u001b[0;34m(self, typ, value, traceback)\u001b[0m\n\u001b[1;32m    157\u001b[0m \u001b[38;5;28;01mtry\u001b[39;00m:\n\u001b[0;32m--> 158\u001b[0m     \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mgen\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mthrow\u001b[49m\u001b[43m(\u001b[49m\u001b[43mvalue\u001b[49m\u001b[43m)\u001b[49m\n\u001b[1;32m    159\u001b[0m \u001b[38;5;28;01mexcept\u001b[39;00m \u001b[38;5;167;01mStopIteration\u001b[39;00m \u001b[38;5;28;01mas\u001b[39;00m exc:\n\u001b[1;32m    160\u001b[0m     \u001b[38;5;66;03m# Suppress StopIteration *unless* it's the same exception that\u001b[39;00m\n\u001b[1;32m    161\u001b[0m     \u001b[38;5;66;03m# was passed to throw().  This prevents a StopIteration\u001b[39;00m\n\u001b[1;32m    162\u001b[0m     \u001b[38;5;66;03m# raised inside the \"with\" statement from being suppressed.\u001b[39;00m\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/httpx/_transports/default.py:86\u001b[0m, in \u001b[0;36mmap_httpcore_exceptions\u001b[0;34m()\u001b[0m\n\u001b[1;32m     85\u001b[0m message \u001b[38;5;241m=\u001b[39m \u001b[38;5;28mstr\u001b[39m(exc)\n\u001b[0;32m---> 86\u001b[0m \u001b[38;5;28;01mraise\u001b[39;00m mapped_exc(message) \u001b[38;5;28;01mfrom\u001b[39;00m \u001b[38;5;21;01mexc\u001b[39;00m\n",
+      "\u001b[0;31mConnectError\u001b[0m: [SSL: UNEXPECTED_EOF_WHILE_READING] EOF occurred in violation of protocol (_ssl.c:1000)",
+      "\nThe above exception was the direct cause of the following exception:\n",
+      "\u001b[0;31mAPIConnectionError\u001b[0m                        Traceback (most recent call last)",
+      "Cell \u001b[0;32mIn[55], line 17\u001b[0m\n\u001b[1;32m     15\u001b[0m     \u001b[38;5;28mprint\u001b[39m(filename)\n\u001b[1;32m     16\u001b[0m     \u001b[38;5;66;03m# await generate_edge_tts_audio(sentence, filename, voice=voice, verbose=True, overwrite=True, play=True)\u001b[39;00m\n\u001b[0;32m---> 17\u001b[0m     \u001b[43mget_openai_tts_audio\u001b[49m\u001b[43m(\u001b[49m\u001b[43msentence\u001b[49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[43mfilename\u001b[49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[43mperformer\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mvoice\u001b[49m\u001b[43m)\u001b[49m\n\u001b[1;32m     21\u001b[0m \u001b[38;5;66;03m# get_openai_tts_audio(sentence, f'../audios/{sentence.replace(\" \", \"-\")}-alloy.mp3', performer='alloy')\u001b[39;00m\n\u001b[1;32m     22\u001b[0m \u001b[38;5;66;03m# get_openai_tts_audio(sentence, f'../audios/{sentence.replace(\" \", \"-\")}-nova.mp3', performer='nova')\u001b[39;00m\n",
+      "Cell \u001b[0;32mIn[21], line 9\u001b[0m, in \u001b[0;36mget_openai_tts_audio\u001b[0;34m(text, path, performer)\u001b[0m\n\u001b[1;32m      5\u001b[0m load_dotenv()\n\u001b[1;32m      6\u001b[0m client \u001b[38;5;241m=\u001b[39m OpenAI(\n\u001b[1;32m      7\u001b[0m )\n\u001b[0;32m----> 9\u001b[0m \u001b[43m\u001b[49m\u001b[38;5;28;43;01mwith\u001b[39;49;00m\u001b[43m \u001b[49m\u001b[43mclient\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43maudio\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mspeech\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mwith_streaming_response\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mcreate\u001b[49m\u001b[43m(\u001b[49m\n\u001b[1;32m     10\u001b[0m \u001b[43m    \u001b[49m\u001b[43mmodel\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43mtts-1\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m,\u001b[49m\n\u001b[1;32m     11\u001b[0m \u001b[43m    \u001b[49m\u001b[43mvoice\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mperformer\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m     12\u001b[0m \u001b[43m    \u001b[49m\u001b[38;5;28;43minput\u001b[39;49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mtext\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mstrip\u001b[49m\u001b[43m(\u001b[49m\u001b[43m)\u001b[49m\n\u001b[1;32m     13\u001b[0m \u001b[43m\u001b[49m\u001b[43m)\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;28;43;01mas\u001b[39;49;00m\u001b[43m \u001b[49m\u001b[43mresponse\u001b[49m\u001b[43m:\u001b[49m\n\u001b[1;32m     14\u001b[0m \u001b[43m    \u001b[49m\u001b[43mresponse\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mstream_to_file\u001b[49m\u001b[43m(\u001b[49m\u001b[43mpath\u001b[49m\u001b[43m)\u001b[49m\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/openai/_response.py:615\u001b[0m, in \u001b[0;36mResponseContextManager.__enter__\u001b[0;34m(self)\u001b[0m\n\u001b[1;32m    614\u001b[0m \u001b[38;5;28;01mdef\u001b[39;00m \u001b[38;5;21m__enter__\u001b[39m(\u001b[38;5;28mself\u001b[39m) \u001b[38;5;241m-\u001b[39m\u001b[38;5;241m>\u001b[39m _APIResponseT:\n\u001b[0;32m--> 615\u001b[0m     \u001b[38;5;28mself\u001b[39m\u001b[38;5;241m.\u001b[39m__response \u001b[38;5;241m=\u001b[39m \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43m_request_func\u001b[49m\u001b[43m(\u001b[49m\u001b[43m)\u001b[49m\n\u001b[1;32m    616\u001b[0m     \u001b[38;5;28;01mreturn\u001b[39;00m \u001b[38;5;28mself\u001b[39m\u001b[38;5;241m.\u001b[39m__response\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/openai/resources/audio/speech.py:85\u001b[0m, in \u001b[0;36mSpeech.create\u001b[0;34m(self, input, model, voice, response_format, speed, extra_headers, extra_query, extra_body, timeout)\u001b[0m\n\u001b[1;32m     55\u001b[0m \u001b[38;5;250m\u001b[39m\u001b[38;5;124;03m\"\"\"\u001b[39;00m\n\u001b[1;32m     56\u001b[0m \u001b[38;5;124;03mGenerates audio from the input text.\u001b[39;00m\n\u001b[1;32m     57\u001b[0m \n\u001b[0;32m   (...)\u001b[0m\n\u001b[1;32m     82\u001b[0m \u001b[38;5;124;03m  timeout: Override the client-level default timeout for this request, in seconds\u001b[39;00m\n\u001b[1;32m     83\u001b[0m \u001b[38;5;124;03m\"\"\"\u001b[39;00m\n\u001b[1;32m     84\u001b[0m extra_headers \u001b[38;5;241m=\u001b[39m {\u001b[38;5;124m\"\u001b[39m\u001b[38;5;124mAccept\u001b[39m\u001b[38;5;124m\"\u001b[39m: \u001b[38;5;124m\"\u001b[39m\u001b[38;5;124mapplication/octet-stream\u001b[39m\u001b[38;5;124m\"\u001b[39m, \u001b[38;5;241m*\u001b[39m\u001b[38;5;241m*\u001b[39m(extra_headers \u001b[38;5;129;01mor\u001b[39;00m {})}\n\u001b[0;32m---> 85\u001b[0m \u001b[38;5;28;01mreturn\u001b[39;00m \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43m_post\u001b[49m\u001b[43m(\u001b[49m\n\u001b[1;32m     86\u001b[0m \u001b[43m    \u001b[49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43m/audio/speech\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m,\u001b[49m\n\u001b[1;32m     87\u001b[0m \u001b[43m    \u001b[49m\u001b[43mbody\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mmaybe_transform\u001b[49m\u001b[43m(\u001b[49m\n\u001b[1;32m     88\u001b[0m \u001b[43m        \u001b[49m\u001b[43m{\u001b[49m\n\u001b[1;32m     89\u001b[0m \u001b[43m            \u001b[49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43minput\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m:\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;28;43minput\u001b[39;49m\u001b[43m,\u001b[49m\n\u001b[1;32m     90\u001b[0m \u001b[43m            \u001b[49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43mmodel\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m:\u001b[49m\u001b[43m \u001b[49m\u001b[43mmodel\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m     91\u001b[0m \u001b[43m            \u001b[49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43mvoice\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m:\u001b[49m\u001b[43m \u001b[49m\u001b[43mvoice\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m     92\u001b[0m \u001b[43m            \u001b[49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43mresponse_format\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m:\u001b[49m\u001b[43m \u001b[49m\u001b[43mresponse_format\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m     93\u001b[0m \u001b[43m            \u001b[49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43mspeed\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m:\u001b[49m\u001b[43m \u001b[49m\u001b[43mspeed\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m     94\u001b[0m \u001b[43m        \u001b[49m\u001b[43m}\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m     95\u001b[0m \u001b[43m        \u001b[49m\u001b[43mspeech_create_params\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mSpeechCreateParams\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m     96\u001b[0m \u001b[43m    \u001b[49m\u001b[43m)\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m     97\u001b[0m \u001b[43m    \u001b[49m\u001b[43moptions\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mmake_request_options\u001b[49m\u001b[43m(\u001b[49m\n\u001b[1;32m     98\u001b[0m \u001b[43m        \u001b[49m\u001b[43mextra_headers\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mextra_headers\u001b[49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[43mextra_query\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mextra_query\u001b[49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[43mextra_body\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mextra_body\u001b[49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[43mtimeout\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mtimeout\u001b[49m\n\u001b[1;32m     99\u001b[0m \u001b[43m    \u001b[49m\u001b[43m)\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    100\u001b[0m \u001b[43m    \u001b[49m\u001b[43mcast_to\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43m_legacy_response\u001b[49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mHttpxBinaryResponseContent\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    101\u001b[0m \u001b[43m\u001b[49m\u001b[43m)\u001b[49m\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/openai/_base_client.py:1271\u001b[0m, in \u001b[0;36mSyncAPIClient.post\u001b[0;34m(self, path, cast_to, body, options, files, stream, stream_cls)\u001b[0m\n\u001b[1;32m   1257\u001b[0m \u001b[38;5;28;01mdef\u001b[39;00m \u001b[38;5;21mpost\u001b[39m(\n\u001b[1;32m   1258\u001b[0m     \u001b[38;5;28mself\u001b[39m,\n\u001b[1;32m   1259\u001b[0m     path: \u001b[38;5;28mstr\u001b[39m,\n\u001b[0;32m   (...)\u001b[0m\n\u001b[1;32m   1266\u001b[0m     stream_cls: \u001b[38;5;28mtype\u001b[39m[_StreamT] \u001b[38;5;241m|\u001b[39m \u001b[38;5;28;01mNone\u001b[39;00m \u001b[38;5;241m=\u001b[39m \u001b[38;5;28;01mNone\u001b[39;00m,\n\u001b[1;32m   1267\u001b[0m ) \u001b[38;5;241m-\u001b[39m\u001b[38;5;241m>\u001b[39m ResponseT \u001b[38;5;241m|\u001b[39m _StreamT:\n\u001b[1;32m   1268\u001b[0m     opts \u001b[38;5;241m=\u001b[39m FinalRequestOptions\u001b[38;5;241m.\u001b[39mconstruct(\n\u001b[1;32m   1269\u001b[0m         method\u001b[38;5;241m=\u001b[39m\u001b[38;5;124m\"\u001b[39m\u001b[38;5;124mpost\u001b[39m\u001b[38;5;124m\"\u001b[39m, url\u001b[38;5;241m=\u001b[39mpath, json_data\u001b[38;5;241m=\u001b[39mbody, files\u001b[38;5;241m=\u001b[39mto_httpx_files(files), \u001b[38;5;241m*\u001b[39m\u001b[38;5;241m*\u001b[39moptions\n\u001b[1;32m   1270\u001b[0m     )\n\u001b[0;32m-> 1271\u001b[0m     \u001b[38;5;28;01mreturn\u001b[39;00m cast(ResponseT, \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43mrequest\u001b[49m\u001b[43m(\u001b[49m\u001b[43mcast_to\u001b[49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[43mopts\u001b[49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[43mstream\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mstream\u001b[49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[43mstream_cls\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mstream_cls\u001b[49m\u001b[43m)\u001b[49m)\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/openai/_base_client.py:942\u001b[0m, in \u001b[0;36mSyncAPIClient.request\u001b[0;34m(self, cast_to, options, remaining_retries, stream, stream_cls)\u001b[0m\n\u001b[1;32m    933\u001b[0m \u001b[38;5;28;01mdef\u001b[39;00m \u001b[38;5;21mrequest\u001b[39m(\n\u001b[1;32m    934\u001b[0m     \u001b[38;5;28mself\u001b[39m,\n\u001b[1;32m    935\u001b[0m     cast_to: Type[ResponseT],\n\u001b[0;32m   (...)\u001b[0m\n\u001b[1;32m    940\u001b[0m     stream_cls: \u001b[38;5;28mtype\u001b[39m[_StreamT] \u001b[38;5;241m|\u001b[39m \u001b[38;5;28;01mNone\u001b[39;00m \u001b[38;5;241m=\u001b[39m \u001b[38;5;28;01mNone\u001b[39;00m,\n\u001b[1;32m    941\u001b[0m ) \u001b[38;5;241m-\u001b[39m\u001b[38;5;241m>\u001b[39m ResponseT \u001b[38;5;241m|\u001b[39m _StreamT:\n\u001b[0;32m--> 942\u001b[0m     \u001b[38;5;28;01mreturn\u001b[39;00m \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43m_request\u001b[49m\u001b[43m(\u001b[49m\n\u001b[1;32m    943\u001b[0m \u001b[43m        \u001b[49m\u001b[43mcast_to\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mcast_to\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    944\u001b[0m \u001b[43m        \u001b[49m\u001b[43moptions\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43moptions\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    945\u001b[0m \u001b[43m        \u001b[49m\u001b[43mstream\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mstream\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    946\u001b[0m \u001b[43m        \u001b[49m\u001b[43mstream_cls\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mstream_cls\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    947\u001b[0m \u001b[43m        \u001b[49m\u001b[43mremaining_retries\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mremaining_retries\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m    948\u001b[0m \u001b[43m    \u001b[49m\u001b[43m)\u001b[49m\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/openai/_base_client.py:1002\u001b[0m, in \u001b[0;36mSyncAPIClient._request\u001b[0;34m(self, cast_to, options, remaining_retries, stream, stream_cls)\u001b[0m\n\u001b[1;32m    999\u001b[0m log\u001b[38;5;241m.\u001b[39mdebug(\u001b[38;5;124m\"\u001b[39m\u001b[38;5;124mEncountered Exception\u001b[39m\u001b[38;5;124m\"\u001b[39m, exc_info\u001b[38;5;241m=\u001b[39m\u001b[38;5;28;01mTrue\u001b[39;00m)\n\u001b[1;32m   1001\u001b[0m \u001b[38;5;28;01mif\u001b[39;00m retries \u001b[38;5;241m>\u001b[39m \u001b[38;5;241m0\u001b[39m:\n\u001b[0;32m-> 1002\u001b[0m     \u001b[38;5;28;01mreturn\u001b[39;00m \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43m_retry_request\u001b[49m\u001b[43m(\u001b[49m\n\u001b[1;32m   1003\u001b[0m \u001b[43m        \u001b[49m\u001b[43minput_options\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1004\u001b[0m \u001b[43m        \u001b[49m\u001b[43mcast_to\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1005\u001b[0m \u001b[43m        \u001b[49m\u001b[43mretries\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1006\u001b[0m \u001b[43m        \u001b[49m\u001b[43mstream\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mstream\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1007\u001b[0m \u001b[43m        \u001b[49m\u001b[43mstream_cls\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mstream_cls\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1008\u001b[0m \u001b[43m        \u001b[49m\u001b[43mresponse_headers\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[38;5;28;43;01mNone\u001b[39;49;00m\u001b[43m,\u001b[49m\n\u001b[1;32m   1009\u001b[0m \u001b[43m    \u001b[49m\u001b[43m)\u001b[49m\n\u001b[1;32m   1011\u001b[0m log\u001b[38;5;241m.\u001b[39mdebug(\u001b[38;5;124m\"\u001b[39m\u001b[38;5;124mRaising connection error\u001b[39m\u001b[38;5;124m\"\u001b[39m)\n\u001b[1;32m   1012\u001b[0m \u001b[38;5;28;01mraise\u001b[39;00m APIConnectionError(request\u001b[38;5;241m=\u001b[39mrequest) \u001b[38;5;28;01mfrom\u001b[39;00m \u001b[38;5;21;01merr\u001b[39;00m\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/openai/_base_client.py:1080\u001b[0m, in \u001b[0;36mSyncAPIClient._retry_request\u001b[0;34m(self, options, cast_to, remaining_retries, response_headers, stream, stream_cls)\u001b[0m\n\u001b[1;32m   1076\u001b[0m \u001b[38;5;66;03m# In a synchronous context we are blocking the entire thread. Up to the library user to run the client in a\u001b[39;00m\n\u001b[1;32m   1077\u001b[0m \u001b[38;5;66;03m# different thread if necessary.\u001b[39;00m\n\u001b[1;32m   1078\u001b[0m time\u001b[38;5;241m.\u001b[39msleep(timeout)\n\u001b[0;32m-> 1080\u001b[0m \u001b[38;5;28;01mreturn\u001b[39;00m \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43m_request\u001b[49m\u001b[43m(\u001b[49m\n\u001b[1;32m   1081\u001b[0m \u001b[43m    \u001b[49m\u001b[43moptions\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43moptions\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1082\u001b[0m \u001b[43m    \u001b[49m\u001b[43mcast_to\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mcast_to\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1083\u001b[0m \u001b[43m    \u001b[49m\u001b[43mremaining_retries\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mremaining\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1084\u001b[0m \u001b[43m    \u001b[49m\u001b[43mstream\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mstream\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1085\u001b[0m \u001b[43m    \u001b[49m\u001b[43mstream_cls\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mstream_cls\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1086\u001b[0m \u001b[43m\u001b[49m\u001b[43m)\u001b[49m\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/openai/_base_client.py:1002\u001b[0m, in \u001b[0;36mSyncAPIClient._request\u001b[0;34m(self, cast_to, options, remaining_retries, stream, stream_cls)\u001b[0m\n\u001b[1;32m    999\u001b[0m log\u001b[38;5;241m.\u001b[39mdebug(\u001b[38;5;124m\"\u001b[39m\u001b[38;5;124mEncountered Exception\u001b[39m\u001b[38;5;124m\"\u001b[39m, exc_info\u001b[38;5;241m=\u001b[39m\u001b[38;5;28;01mTrue\u001b[39;00m)\n\u001b[1;32m   1001\u001b[0m \u001b[38;5;28;01mif\u001b[39;00m retries \u001b[38;5;241m>\u001b[39m \u001b[38;5;241m0\u001b[39m:\n\u001b[0;32m-> 1002\u001b[0m     \u001b[38;5;28;01mreturn\u001b[39;00m \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43m_retry_request\u001b[49m\u001b[43m(\u001b[49m\n\u001b[1;32m   1003\u001b[0m \u001b[43m        \u001b[49m\u001b[43minput_options\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1004\u001b[0m \u001b[43m        \u001b[49m\u001b[43mcast_to\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1005\u001b[0m \u001b[43m        \u001b[49m\u001b[43mretries\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1006\u001b[0m \u001b[43m        \u001b[49m\u001b[43mstream\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mstream\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1007\u001b[0m \u001b[43m        \u001b[49m\u001b[43mstream_cls\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mstream_cls\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1008\u001b[0m \u001b[43m        \u001b[49m\u001b[43mresponse_headers\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[38;5;28;43;01mNone\u001b[39;49;00m\u001b[43m,\u001b[49m\n\u001b[1;32m   1009\u001b[0m \u001b[43m    \u001b[49m\u001b[43m)\u001b[49m\n\u001b[1;32m   1011\u001b[0m log\u001b[38;5;241m.\u001b[39mdebug(\u001b[38;5;124m\"\u001b[39m\u001b[38;5;124mRaising connection error\u001b[39m\u001b[38;5;124m\"\u001b[39m)\n\u001b[1;32m   1012\u001b[0m \u001b[38;5;28;01mraise\u001b[39;00m APIConnectionError(request\u001b[38;5;241m=\u001b[39mrequest) \u001b[38;5;28;01mfrom\u001b[39;00m \u001b[38;5;21;01merr\u001b[39;00m\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/openai/_base_client.py:1080\u001b[0m, in \u001b[0;36mSyncAPIClient._retry_request\u001b[0;34m(self, options, cast_to, remaining_retries, response_headers, stream, stream_cls)\u001b[0m\n\u001b[1;32m   1076\u001b[0m \u001b[38;5;66;03m# In a synchronous context we are blocking the entire thread. Up to the library user to run the client in a\u001b[39;00m\n\u001b[1;32m   1077\u001b[0m \u001b[38;5;66;03m# different thread if necessary.\u001b[39;00m\n\u001b[1;32m   1078\u001b[0m time\u001b[38;5;241m.\u001b[39msleep(timeout)\n\u001b[0;32m-> 1080\u001b[0m \u001b[38;5;28;01mreturn\u001b[39;00m \u001b[38;5;28;43mself\u001b[39;49m\u001b[38;5;241;43m.\u001b[39;49m\u001b[43m_request\u001b[49m\u001b[43m(\u001b[49m\n\u001b[1;32m   1081\u001b[0m \u001b[43m    \u001b[49m\u001b[43moptions\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43moptions\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1082\u001b[0m \u001b[43m    \u001b[49m\u001b[43mcast_to\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mcast_to\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1083\u001b[0m \u001b[43m    \u001b[49m\u001b[43mremaining_retries\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mremaining\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1084\u001b[0m \u001b[43m    \u001b[49m\u001b[43mstream\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mstream\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1085\u001b[0m \u001b[43m    \u001b[49m\u001b[43mstream_cls\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43mstream_cls\u001b[49m\u001b[43m,\u001b[49m\n\u001b[1;32m   1086\u001b[0m \u001b[43m\u001b[49m\u001b[43m)\u001b[49m\n",
+      "File \u001b[0;32m/opt/homebrew/Caskroom/miniconda/base/lib/python3.12/site-packages/openai/_base_client.py:1012\u001b[0m, in \u001b[0;36mSyncAPIClient._request\u001b[0;34m(self, cast_to, options, remaining_retries, stream, stream_cls)\u001b[0m\n\u001b[1;32m   1002\u001b[0m         \u001b[38;5;28;01mreturn\u001b[39;00m \u001b[38;5;28mself\u001b[39m\u001b[38;5;241m.\u001b[39m_retry_request(\n\u001b[1;32m   1003\u001b[0m             input_options,\n\u001b[1;32m   1004\u001b[0m             cast_to,\n\u001b[0;32m   (...)\u001b[0m\n\u001b[1;32m   1008\u001b[0m             response_headers\u001b[38;5;241m=\u001b[39m\u001b[38;5;28;01mNone\u001b[39;00m,\n\u001b[1;32m   1009\u001b[0m         )\n\u001b[1;32m   1011\u001b[0m     log\u001b[38;5;241m.\u001b[39mdebug(\u001b[38;5;124m\"\u001b[39m\u001b[38;5;124mRaising connection error\u001b[39m\u001b[38;5;124m\"\u001b[39m)\n\u001b[0;32m-> 1012\u001b[0m     \u001b[38;5;28;01mraise\u001b[39;00m APIConnectionError(request\u001b[38;5;241m=\u001b[39mrequest) \u001b[38;5;28;01mfrom\u001b[39;00m \u001b[38;5;21;01merr\u001b[39;00m\n\u001b[1;32m   1014\u001b[0m log\u001b[38;5;241m.\u001b[39mdebug(\n\u001b[1;32m   1015\u001b[0m     \u001b[38;5;124m'\u001b[39m\u001b[38;5;124mHTTP Response: \u001b[39m\u001b[38;5;132;01m%s\u001b[39;00m\u001b[38;5;124m \u001b[39m\u001b[38;5;132;01m%s\u001b[39;00m\u001b[38;5;124m \u001b[39m\u001b[38;5;124m\"\u001b[39m\u001b[38;5;132;01m%i\u001b[39;00m\u001b[38;5;124m \u001b[39m\u001b[38;5;132;01m%s\u001b[39;00m\u001b[38;5;124m\"\u001b[39m\u001b[38;5;124m \u001b[39m\u001b[38;5;132;01m%s\u001b[39;00m\u001b[38;5;124m'\u001b[39m,\n\u001b[1;32m   1016\u001b[0m     request\u001b[38;5;241m.\u001b[39mmethod,\n\u001b[0;32m   (...)\u001b[0m\n\u001b[1;32m   1020\u001b[0m     response\u001b[38;5;241m.\u001b[39mheaders,\n\u001b[1;32m   1021\u001b[0m )\n\u001b[1;32m   1022\u001b[0m log\u001b[38;5;241m.\u001b[39mdebug(\u001b[38;5;124m\"\u001b[39m\u001b[38;5;124mrequest_id: \u001b[39m\u001b[38;5;132;01m%s\u001b[39;00m\u001b[38;5;124m\"\u001b[39m, response\u001b[38;5;241m.\u001b[39mheaders\u001b[38;5;241m.\u001b[39mget(\u001b[38;5;124m\"\u001b[39m\u001b[38;5;124mx-request-id\u001b[39m\u001b[38;5;124m\"\u001b[39m))\n",
+      "\u001b[0;31mAPIConnectionError\u001b[0m: Connection error."
      ]
     }
    ],
    "source": [
     "# generate sentences using edge-tts\n",
     "sentences = \"\"\"\n",
-    "ten cups\n",
-    "increase\n",
-    "brown gate\n",
+    "It's our pleasure.\n",
     "\"\"\"\n",
     "# split the sentences into lines\n",
     "sentences = [s for s in sentences.strip().split(\"\\n\") if s]\n",
diff --git a/1000-hours/sounds-of-american-english-old/0-intro.md b/1000-hours/sounds-of-american-english-old/0-intro.md
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-# 美式英语语音基础教程
-
-自然语音中最基础的、不可分割的单位是**音素**（*phonemes*）；音素构成**音节**（*syllables*）；音节构成**词汇**（*words*）；词汇构成**意群**（*thought groups*）；意群构成**句子**（*sentences*)；句子构成**语篇**（*discourse*）—— 而一方说出的语篇（无论长短、无论完整与否）要被对方听到并理解，这样才能启动**对话**（*dialogue*）
-
-The most fundamental and indivisible unit in natural speech is the *phoneme*; phonemes form *syllables*; syllables form *words*; words form *thought groups*; thought groups form *sentences*; sentences form *discourse* - and a discourse spoken by one party (regardless of its length or completeness) needs to be heard and understood by the other party to initiate a *dialogue*.
-
-音素的准确与否，长期被认为是最重要的基础，甚至被认为是最关键的决定性因素。然而，在音素准确与否之上，更为重要的是说话的方式，即，语音的**韵律**（*prosody*）和**节奏**（*rhythm*）。所以，我们的教程将以**音节**为中心，主要关注**韵律**和**节奏** —— 当然，我们也只能从音素讲起。
-
-The accuracy of phonemes has long been considered the most critical foundation, even regarded as the key determinant. However, more important than phoneme accuracy is the way of speaking, that is, the *prosody* and *rhythm* of speech. Therefore, our tutorial will center on *syllables*, primarily focusing on *prosody* and *rhythm*—of course, we have to start with phonemes.
-
-另外，这是一个**零基础教程**，所以，完全不用担心自己基础差。在教程里，我们从音素开始讲起，而音素，根据定义，就是自然语音的最基础内容 —— 实在不可能有什么比它更基础的了 —— 所以，在此之前不需要有任何预备知识。
-
-Moreover, this is a tutorial for beginners, meaning there's no need to worry if you feel that you lack the basics. We will start from phonemes, which, by definition, are the most fundamental elements of spoken language. There's nothing more basic than this, therefore, *there's no need for any prior knowledge to start this course*.
\ No newline at end of file
diff --git a/1000-hours/sounds-of-american-english-old/1-basics.md b/1000-hours/sounds-of-american-english-old/1-basics.md
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-# 1. 基础（Basics）
-
-英文语音所谓的基础真的很少，打印出来也不过是几页纸的篇幅而已…… 实际上，任何语音的语音基础知识都同样少得惊人。
-
-The fundamentals of English pronunciation, in reality, are quite straightforward. Printed out, they would only take up a few pages. In fact, the basic knowledge of any language's pronunciation is astonishingly limited.
\ No newline at end of file
diff --git a/1000-hours/sounds-of-american-english-old/1.1-alphabet.md b/1000-hours/sounds-of-american-english-old/1.1-alphabet.md
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-# 1.1 字母（Alphabet）
-
-英语总计使用 26 个**字母**（*letters*），各有大小写之分。在欧洲语言之中，英语是罕见的不使用**修饰符**（*diacritics*）的文字 —— 所谓修饰符，指的是字母上附加的标记，用以区分发音或者意义，比如，*â*、*é*、*ç*，等等。
-
-Modern English is composed of *26* letters, each with both *uppercase* and *lowercase* forms. English stands out among European languages for not using [diacritics](https://en.wikipedia.org/wiki/Diacritic), which are special marks added to letters to alter their pronunciation or meaning, such as *â*, *é* or *ç*, etc.
-
-北约（NATO）有一套指称英文字母的系统，用以在仅有语音交流的情况下避免歧义 —— 在军事、航空、紧急救助、无线电或者电话沟通等诸多场合中具备不可或缺的作用。
-
-[NATO](https://en.wikipedia.org/wiki/NATO) has a system that uses common words to identify each letter, which is particularly helpful for military and civil aviation, emergency serivces, radio or phone communication, and many others to avoid confusion when spelling out words.
-
-| Letter    | Pronunciation                                                                                                                                      | NATO Phonetic Alphabet                                                                                                                                                      |
-| --------- | -------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| **A** *a* | <span class="pho alt">eɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/a-us-guy.mp3" data-audio-us-female="/audios/us/a-us-jen.mp3"></span>          | *Alpha*    <span class="pho alt">ˈælfə</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Alpha-us-guy.mp3" data-audio-us-female="/audios/us/Alpha-us-jen.mp3"></span>            |
-| **B** *b* | <span class="pho alt">biː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/b-us-guy.mp3" data-audio-us-female="/audios/us/b-us-jen.mp3"></span>         | *Bravo*    <span class="pho alt">ˈbrɑːvoʊ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Bravo-us-guy.mp3" data-audio-us-female="/audios/us/Bravo-us-jen.mp3"></span>         |
-| **C** *c* | <span class="pho alt">siː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/c-us-guy.mp3" data-audio-us-female="/audios/us/c-us-jen.mp3"></span>         | *Charlie*  <span class="pho alt">ˈtʃɑːrli</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Charlie-us-guy.mp3" data-audio-us-female="/audios/us/Charlie-us-jen.mp3"></span>    |
-| **D** *d* | <span class="pho alt">diː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/d-us-guy.mp3" data-audio-us-female="/audios/us/d-us-jen.mp3"></span>         | *Delta*    <span class="pho alt">ˈdeltə</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Delta-us-guy.mp3" data-audio-us-female="/audios/us/Delta-us-jen.mp3"></span>           |
-| **E** *e* | <span class="pho alt">iː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/e-us-guy.mp3" data-audio-us-female="/audios/us/e-us-jen.mp3"></span>          | *Echo*     <span class="pho alt">ˈekoʊ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Echo-us-guy.mp3" data-audio-us-female="/audios/us/Echo-us-jen.mp3"></span>              |
-| **F** *f* | <span class="pho alt">ef</span><span class="speak-word-inline" data-audio-us-male="/audios/us/f-us-guy.mp3" data-audio-us-female="/audios/us/f-us-jen.mp3"></span>          | *Foxtrot*  <span class="pho alt">ˈfɔːkstrɒt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Foxtrot-us-guy.mp3" data-audio-us-female="/audios/us/Foxtrot-us-jen.mp3"></span>   |
-| **G** *g* | <span class="pho alt">dʒiː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/g-us-guy.mp3" data-audio-us-female="/audios/us/g-us-jen.mp3"></span>        | *Golf*     <span class="pho alt">ɡɑːf</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Golf-us-guy.mp3" data-audio-us-female="/audios/us/Golf-us-jen.mp3"></span>                |
-| **H** *h* | <span class="pho alt">eɪtʃ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/h-us-guy.mp3" data-audio-us-female="/audios/us/h-us-jen.mp3"></span>        | *Hotel*    <span class="pho alt">hoʊˈtel</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Hotel-us-guy.mp3" data-audio-us-female="/audios/us/Hotel-us-jen.mp3"></span>           |
-| **I** *i* | <span class="pho alt">aɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/i-us-guy.mp3" data-audio-us-female="/audios/us/i-us-jen.mp3"></span>          | *India*    <span class="pho alt">ˈɪndiə</span><span class="speak-word-inline" data-audio-us-male="/audios/us/India-us-guy.mp3" data-audio-us-female="/audios/us/India-us-jen.mp3"></span>          |
-| **J** *j* | <span class="pho alt">dʒeɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/j-us-guy.mp3" data-audio-us-female="/audios/us/j-us-jen.mp3"></span>        | *Juliet*   <span class="pho alt">ˈdʒuːliət, ˈdʒuːliˌet</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Juliet-us-guy.mp3" data-audio-us-female="/audios/us/Juliet-us-jen.mp3"></span>     |
-| **K** *k* | <span class="pho alt">keɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/k-us-guy.mp3" data-audio-us-female="/audios/us/k-us-jen.mp3"></span>         | *Kilo*     <span class="pho alt">ˈkiːloʊ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Kilo-us-guy.mp3" data-audio-us-female="/audios/us/Kilo-us-jen.mp3"></span>            |
-| **L** *l* | <span class="pho alt">el</span><span class="speak-word-inline" data-audio-us-male="/audios/us/l-us-guy.mp3" data-audio-us-female="/audios/us/l-us-jen.mp3"></span>          | *Lima*     <span class="pho alt">ˈliːmə</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Lima-us-guy.mp3" data-audio-us-female="/audios/us/Lima-us-jen.mp3"></span>             |
-| **M** *m* | <span class="pho alt">em</span><span class="speak-word-inline" data-audio-us-male="/audios/us/m-us-guy.mp3" data-audio-us-female="/audios/us/m-us-jen.mp3"></span>          | *Mike*     <span class="pho alt">maɪk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Mike-us-guy.mp3" data-audio-us-female="/audios/us/Mike-us-jen.mp3"></span>                |
-| **N** *n* | <span class="pho alt">en</span><span class="speak-word-inline" data-audio-us-male="/audios/us/n-us-guy.mp3" data-audio-us-female="/audios/us/n-us-jen.mp3"></span>          | *November* <span class="pho alt">noʊˈvembɚ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/November-us-guy.mp3" data-audio-us-female="/audios/us/November-us-jen.mp3"></span> |
-| **O** *o* | <span class="pho alt">oʊ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/o-us-guy.mp3" data-audio-us-female="/audios/us/o-us-jen.mp3"></span>          | *Oscar*    <span class="pho alt">ˈɑːskɑːr</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Oscar-us-guy.mp3" data-audio-us-female="/audios/us/Oscar-us-jen.mp3"></span>         |
-| **P** *p* | <span class="pho alt">piː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/p-us-guy.mp3" data-audio-us-female="/audios/us/p-us-jen.mp3"></span>         | *Papa*     <span class="pho alt">ˈpɑːpɑ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Papa-us-guy.mp3" data-audio-us-female="/audios/us/Papa-us-jen.mp3"></span>              |
-| **Q** *q* | <span class="pho alt">kjuː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/q-us-guy.mp3" data-audio-us-female="/audios/us/q-us-jen.mp3"></span>        | *Quebec*   <span class="pho alt">kwəˈbek</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Quebec-us-guy.mp3" data-audio-us-female="/audios/us/Quebec-us-jen.mp3"></span>          |
-| **R** *r* | <span class="pho alt">ɑːr</span><span class="speak-word-inline" data-audio-us-male="/audios/us/r-us-guy.mp3" data-audio-us-female="/audios/us/r-us-jen.mp3"></span>         | *Romeo*    <span class="pho alt">ˈroʊmioʊ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Romeo-us-guy.mp3" data-audio-us-female="/audios/us/Romeo-us-jen.mp3"></span>       |
-| **S** *s* | <span class="pho alt">es</span><span class="speak-word-inline" data-audio-us-male="/audios/us/s-us-guy.mp3" data-audio-us-female="/audios/us/s-us-jen.mp3"></span>          | *Sierra*   <span class="pho alt">siˈerə</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Sierra-us-guy.mp3" data-audio-us-female="/audios/us/Sierra-us-jen.mp3"></span>         |
-| **T** *t* | <span class="pho alt">tiː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/t-us-guy.mp3" data-audio-us-female="/audios/us/t-us-jen.mp3"></span>         | *Tango*    <span class="pho alt">ˈtæŋɡoʊ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Tango-us-guy.mp3" data-audio-us-female="/audios/us/Tango-us-jen.mp3"></span>          |
-| **U** *u* | <span class="pho alt">juː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/u-us-guy.mp3" data-audio-us-female="/audios/us/u-us-jen.mp3"></span>         | *Uniform*  <span class="pho alt">ˈjuːnəfɔːrm</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Uniform-us-guy.mp3" data-audio-us-female="/audios/us/Uniform-us-jen.mp3"></span> |
-| **V** *v* | <span class="pho alt">viː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/v-us-guy.mp3" data-audio-us-female="/audios/us/v-us-jen.mp3"></span>         | *Victor*   <span class="pho alt">ˈvɪktɚ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Victor-us-guy.mp3" data-audio-us-female="/audios/us/Victor-us-jen.mp3"></span>        |
-| **W** *w* | <span class="pho alt">ˈdʌbᵊljuː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/w-us-guy.mp3" data-audio-us-female="/audios/us/w-us-jen.mp3"></span> | *Whiskey*  <span class="pho alt">ˈwɪskiː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Whiskey-us-guy.mp3" data-audio-us-female="/audios/us/Whiskey-us-jen.mp3"></span>      |
-| **X** *x* | <span class="pho alt">eks</span><span class="speak-word-inline" data-audio-us-male="/audios/us/x-us-guy.mp3" data-audio-us-female="/audios/us/x-us-jen.mp3"></span>         | *X-ray*    <span class="pho alt">ˈeks.reɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/X-ray-us-guy.mp3" data-audio-us-female="/audios/us/X-ray-us-jen.mp3"></span>          |
-| **Y** *y* | <span class="pho alt">waɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/y-us-guy.mp3" data-audio-us-female="/audios/us/y-us-jen.mp3"></span>         | *Yankee*   <span class="pho alt">ˈjæŋkiː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Yankee-us-guy.mp3" data-audio-us-female="/audios/us/Yankee-us-jen.mp3"></span>        |
-| **Z** *z* | <span class="pho alt">ziː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/z-us-guy.mp3" data-audio-us-female="/audios/us/z-us-jen.mp3"></span>         | *Zulu*     <span class="pho alt">ˈzuːluː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Zulu-us-guy.mp3" data-audio-us-female="/audios/us/Zulu-us-jen.mp3"></span>            |
-
-在英式英语中，*z* 被读作 <span class="pho alt">zed</span><span class="speak-word-inline" data-audio-uk-female="/audios/us/zed-uk.mp3"></span>。
-
-In British, letter *z* is pronounced as <span class="pho alt">zed</span><span class="speak-word-inline" data-audio-uk-female="/audios/us/zed-uk.mp3"></span>.
-
-> [!Note]
->
-> * 合成语音文件使用的是 OpenAI 的 TTS (Text-to-Speech) 和微软的 Edge's TTS。蓝色喇叭图标<span class="speak-word-inline" data-audio-us-male="/audios/us/Alpha-us-guy.mp3"></span>是男性语音，红色喇叭图标<span class="speak-word-inline" data-audio-us-female="/audios/us/Alpha-us-jen.mp3"></span>是女性语音。
-> * The synthesized audio files primarily utilizes OpenAI's TTS (Text-to-Speech) and Microsoft Edge's TTS. The blue background speaker icon<span class="speak-word-inline" data-audio-us-male="/audios/us/Alpha-us-guy.mp3"></span>represents a male voice, whereas the red background speaker icon<span class="speak-word-inline" data-audio-us-female="/audios/us/Alpha-us-jen.mp3"></span>signifies a female voice.
diff --git a/1000-hours/sounds-of-american-english-old/1.2-phonemes.md b/1000-hours/sounds-of-american-english-old/1.2-phonemes.md
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--- a/1000-hours/sounds-of-american-english-old/1.2-phonemes.md
+++ /dev/null
@@ -1,91 +0,0 @@
-# 1.2. 音素（Phonemes）
-
-在自然语音中，不可继续分割的组成部分被称为**音素**（phonemes）。英语的音素分为**元音**和**辅音**。
-
-In natural speech, indivisible sound segments are referred to as *phonemes*. English language categorizes these phonemes into two types: *vowels* and *consonants*.
-
-英文的**音素**用**音标**标注其发音。遗憾的是，英文音标标注方式并不统一。
-
-In English, **phonemes** are annotated by **phonetic symbols** to indicate pronunciation. Unfortunately, there's no universal standard for English phonetic notation.
-
-我们在这里采用了 [Cambridge English Pronouncing Dictionary (CEPD)](https://dictionary.cambridge.org/pronunciation/) 的音标标注体系。
-
-Here, we use the phonetic notation system from the [Cambridge English Pronouncing Dictionary](https://dictionary.cambridge.org/pronunciation/).
-
-> [!Note]
->
-> CEPD 的英式英语的音标是 D.J. 音标体系；而它的美式英语的音标采用的是国际音标体系（IPA）；其详细说明请参考 CEPD 的官方网址[^1]：
->
-> The phonetic notation for British English in CEPD uses the D.J. system, while for American English, it adopts the International Phonetic Alphabet (IPA). For a detailed explanation, please refer to the official CEPD website:
->
-> > https://dictionary.cambridge.org/help/phonetics.html
-
-## 1.2.1. 元音（Vowels）
-
-| Vowels                                                                                                               | Examples                                                                                                                                                                              |
-| -------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| <span class="pho">ʌ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_cup_2023feb.mp3"></span>       | c**u**p <span class="pho alt">kʌp</span><span class="speak-word-inline" data-audio-us-male="/audios/us/cup-us-male.mp3" data-audio-us-female="/audios/us/cup-us-female.mp3"></span>                            |
-| <span class="pho">ɑː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_father_2023feb.mp3"></span>   | f**a**ther <span class="pho alt">ˈfɑːðɚ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/father-us-male.mp3" data-audio-us-female="/audios/us/father-us-female.mp3"></span>                |
-| <span class="pho">e</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_head_2023feb.mp3"></span>      | h**ea**d <span class="pho alt">hed</span><span class="speak-word-inline" data-audio-us-male="/audios/us/head-us-male.mp3" data-audio-us-female="/audios/us/head-us-female.mp3"></span>                         |
-| <span class="pho">æ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_hat_2023feb.mp3"></span>       | h**a**t <span class="pho alt">hæt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/hat-us-male.mp3" data-audio-us-female="/audios/us/hat-us-female.mp3"></span>                            |
-| <span class="pho">ə</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_above_2023feb.mp3"></span>     | **a**bove <span class="pho alt">əˈbʌv</span><span class="speak-word-inline" data-audio-us-male="/audios/us/above-us-male.mp3" data-audio-us-female="/audios/us/above-us-female.mp3"></span>                    |
-| <span class="pho">ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_mother_2023feb.mp3"></span>    | moth**er** <span class="pho alt">ˈmʌðɚ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/mother-us-male.mp3" data-audio-us-female="/audios/us/mother-us-female.mp3"></span>                 |
-| <span class="pho">ɝː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_bird_2023feb.mp3"></span>     | b**ir**d <span class="pho alt">bɝːd</span><span class="speak-word-inline" data-audio-us-male="/audios/us/bird-us-male.mp3" data-audio-us-female="/audios/us/bird-us-female.mp3"></span>                        |
-| <span class="pho">ɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_sheep_2023feb.mp3"></span>     | sh**i**p <span class="pho alt">ʃɪp</span><span class="speak-word-inline" data-audio-us-male="/audios/us/ship-us-male.mp3" data-audio-us-female="/audios/us/ship-us-female.mp3"></span>                         |
-| <span class="pho">i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_happy_2023feb.mp3"></span>     | happ**y** <span class="pho alt">ˈhæpi</span><span class="speak-word-inline" data-audio-us-male="/audios/us/happy-us-male.mp3" data-audio-us-female="/audios/us/happy-us-female.mp3"></span>                    |
-| <span class="pho">iː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_sheep_2023feb.mp3"></span>    | sh**ee**p <span class="pho alt">ʃiːp</span><span class="speak-word-inline" data-audio-us-male="/audios/us/sheep-us-male.mp3" data-audio-us-female="/audios/us/sheep-us-female.mp3"></span>                     |
-| <span class="pho">ɔː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_horse_2023feb.mp3"></span>    | h**or**se <span class="pho alt">hɔːrs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/horse-us-male.mp3" data-audio-us-female="/audios/us/horse-us-female.mp3"></span>                    |
-| <span class="pho">ʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_foot_2023feb.mp3"></span>      | f**oo**t <span class="pho alt">fʊt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/foot-us-male.mp3" data-audio-us-female="/audios/us/foot-us-female.mp3"></span>                         |
-| <span class="pho">u</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_situation_2023feb.mp3"></span> | sit**u**ation <span class="pho alt">ˌsɪtʃuˈeɪʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/situation-us-male.mp3" data-audio-us-female="/audios/us/situation-us-female.mp3"></span> |
-| <span class="pho">uː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_blue_2023feb.mp3"></span>     | bl**ue** <span class="pho alt">bluː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/blue-us-male.mp3" data-audio-us-female="/audios/us/blue-us-female.mp3"></span>                        |
-| <span class="pho">eɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_day_2023feb_002.mp3"></span>  | d**ay** <span class="pho alt">deɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/day-us-male.mp3" data-audio-us-female="/audios/us/day-us-female.mp3"></span>                            |
-| <span class="pho">aɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_eye_2023feb.mp3"></span>      | **eye** <span class="pho alt">aɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/eye-us-male.mp3" data-audio-us-female="/audios/us/eye-us-female.mp3"></span>                             |
-| <span class="pho">ɔɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_boy_2023feb.mp3"></span>      | b**oy** <span class="pho alt">bɔɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/boy-us-male.mp3" data-audio-us-female="/audios/us/boy-us-female.mp3"></span>                            |
-| <span class="pho">oʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_nose_2023feb.mp3"></span>     | n**o**se <span class="pho alt">noʊz</span><span class="speak-word-inline" data-audio-us-male="/audios/us/nose-us-male.mp3" data-audio-us-female="/audios/us/nose-us-female.mp3"></span>                        |
-| <span class="pho">aʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_mouth_2023feb.mp3"></span>    | m**ou**th <span class="pho alt">maʊθ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/mouth-us-male.mp3" data-audio-us-female="/audios/us/mouth-us-female.mp3"></span>                     |
-| <span class="pho">ɪr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_ear_2023feb.mp3"></span>      | ear <span class="pho alt">ɪr</span><span class="speak-word-inline" data-audio-us-male="/audios/us/ear-us-male.mp3" data-audio-us-female="/audios/us/ear-us-female.mp3"></span>                                 |
-| <span class="pho">er</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_hair_2023feb.mp3"></span>     | h**air** <span class="pho alt">her</span><span class="speak-word-inline" data-audio-us-male="/audios/us/hair-us-male.mp3" data-audio-us-female="/audios/us/hair-us-female.mp3"></span>                         |
-| <span class="pho">ʊr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_pure_2023feb.mp3"></span>     | p**ure** <span class="pho alt">pjʊr</span><span class="speak-word-inline" data-audio-us-male="/audios/us/pure-us-male.mp3" data-audio-us-female="/audios/us/pure-us-female.mp3"></span>                        |
-| <span class="pho">aɪr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_fire_2023feb.mp3"></span>    | f**ire** <span class="pho alt">faɪr</span><span class="speak-word-inline" data-audio-us-male="/audios/us/fire-us-male.mp3" data-audio-us-female="/audios/us/fire-us-female.mp3"></span>                        |
-| <span class="pho">aʊr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_hour_2023feb.mp3"></span>    | **hour** <span class="pho alt">aʊr</span><span class="speak-word-inline" data-audio-us-male="/audios/us/hour-us-male.mp3" data-audio-us-female="/audios/us/hour-us-female.mp3"></span>                         |
-
-## 1.2.2. 辅音（Consonants）
-
-| Consonants                                                                                                          | Examples                                                                                                                                                                  |
-| ------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| <span class="pho">p</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_pen_2023feb.mp3"></span>      | **p**en <span class="pho alt">pen</span><span class="speak-word-inline" data-audio-us-male="/audios/us/pen-us-male.mp3" data-audio-us-female="/audios/us/pen-us-female.mp3"></span>                |
-| <span class="pho">b</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_book_2023feb.mp3"></span>     | **b**ook <span class="pho alt">bʊk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/book-us-male.mp3" data-audio-us-female="/audios/us/book-us-female.mp3"></span>             |
-| <span class="pho">t</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_town_2023feb.mp3"></span>     | **t**own <span class="pho alt">taʊn</span><span class="speak-word-inline" data-audio-us-male="/audios/us/town-us-male.mp3" data-audio-us-female="/audios/us/town-us-female.mp3"></span>            |
-| <span class="pho">t̬</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_cutting_2023feb.mp3"></span>  | cu**tt**ing <span class="pho alt">ˈkʌt̬ɪŋ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/cutting-us-male.mp3" data-audio-us-female="/audios/us/cutting-us-female.mp3"></span> |
-| <span class="pho">d</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_day_2023feb_001.mp3"></span>  | **d**ay <span class="pho alt">deɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/day-us-male.mp3" data-audio-us-female="/audios/us/day-us-female.mp3"></span>                |
-| <span class="pho">k</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_cat_2023feb.mp3"></span>      | **c**at <span class="pho alt">kæt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/cat-us-male.mp3" data-audio-us-female="/audios/us/cat-us-female.mp3"></span>                |
-| <span class="pho">g</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_give_2023feb.mp3"></span>     | **g**ive <span class="pho alt">ɡɪv</span><span class="speak-word-inline" data-audio-us-male="/audios/us/give-us-male.mp3" data-audio-us-female="/audios/us/give-us-female.mp3"></span>             |
-| <span class="pho">f</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_fish_2023feb.mp3"></span>     | **f**ish <span class="pho alt">fɪʃ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/fish-us-male.mp3" data-audio-us-female="/audios/us/fish-us-female.mp3"></span>             |
-| <span class="pho">v</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_very_2023feb.mp3"></span>     | **v**ery <span class="pho alt">ˈveri</span><span class="speak-word-inline" data-audio-us-male="/audios/us/very-us-male.mp3" data-audio-us-female="/audios/us/very-us-female.mp3"></span>           |
-| <span class="pho">s</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_say_2023feb.mp3"></span>      | **s**ay <span class="pho alt">seɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/say-us-male.mp3" data-audio-us-female="/audios/us/say-us-female.mp3"></span>                |
-| <span class="pho">z</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_zoo_2023feb.mp3"></span>      | **z**oo <span class="pho alt">zuː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/zoo-us-male.mp3" data-audio-us-female="/audios/us/zoo-us-female.mp3"></span>                |
-| <span class="pho">θ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_think_2023feb.mp3"></span>    | **th**ink <span class="pho alt">θɪŋk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/think-us-male.mp3" data-audio-us-female="/audios/us/think-us-female.mp3"></span>         |
-| <span class="pho">ð</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_this_2023feb.mp3"></span>     | **th**is <span class="pho alt">ðɪs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/this-us-male.mp3" data-audio-us-female="/audios/us/this-us-female.mp3"></span>             |
-| <span class="pho">ʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_she_2023feb.mp3"></span>      | **sh**e <span class="pho alt">ʃiː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/she-us-male.mp3" data-audio-us-female="/audios/us/she-us-female.mp3"></span>                |
-| <span class="pho">ʒ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_vision_2023feb.mp3"></span>   | vi**si**on <span class="pho alt">ˈvɪʒən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/vision-us-male.mp3" data-audio-us-female="/audios/us/vision-us-female.mp3"></span>    |
-| <span class="pho">h</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_hand_2023feb.mp3"></span>     | **h**and <span class="pho alt">hænd</span><span class="speak-word-inline" data-audio-us-male="/audios/us/hand-us-male.mp3" data-audio-us-female="/audios/us/hand-us-female.mp3"></span>            |
-| <span class="pho">tʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_cheese_2023feb.mp3"></span>  | **ch**eese <span class="pho alt">tʃiːz</span><span class="speak-word-inline" data-audio-us-male="/audios/us/cheese-us-male.mp3" data-audio-us-female="/audios/us/cheese-us-female.mp3"></span>     |
-| <span class="pho">dʒ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_jump_2023feb.mp3"></span>    | **j**ump <span class="pho alt">dʒʌmp</span><span class="speak-word-inline" data-audio-us-male="/audios/us/jump-us-male.mp3" data-audio-us-female="/audios/us/jump-us-female.mp3"></span>           |
-| <span class="pho">ts</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_treats_2023feb.mp3"></span>  | trea**ts** <span class="pho alt">triːts</span><span class="speak-word-inline" data-audio-us-male="/audios/us/treats-us-male.mp3" data-audio-us-female="/audios/us/treats-us-female.mp3"></span>    |
-| <span class="pho">dz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_friends_2023feb.mp3"></span> | frien**ds** <span class="pho alt">frendz</span><span class="speak-word-inline" data-audio-us-male="/audios/us/friends-us-male.mp3" data-audio-us-female="/audios/us/friends-us-female.mp3"></span> |
-| <span class="pho">m</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_moon_2023feb.mp3"></span>     | **m**oon <span class="pho alt">muːn</span><span class="speak-word-inline" data-audio-us-male="/audios/us/moon-us-male.mp3" data-audio-us-female="/audios/us/moon-us-female.mp3"></span>            |
-| <span class="pho">n</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_name_2023feb.mp3"></span>     | **n**ame <span class="pho alt">neɪm</span><span class="speak-word-inline" data-audio-us-male="/audios/us/name-us-male.mp3" data-audio-us-female="/audios/us/name-us-female.mp3"></span>            |
-| <span class="pho">ŋ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_sing_2023feb.mp3"></span>     | si**ng** <span class="pho alt">sɪŋ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/sing-us-male.mp3" data-audio-us-female="/audios/us/sing-us-female.mp3"></span>             |
-| <span class="pho">l</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_look_2023feb.mp3"></span>     | **l**ook <span class="pho alt">lʊk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/look-us-male.mp3" data-audio-us-female="/audios/us/look-us-female.mp3"></span>             |
-| <span class="pho">r</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_run_2023feb.mp3"></span>      | **r**un <span class="pho alt">rʌn</span><span class="speak-word-inline" data-audio-us-male="/audios/us/run-us-male.mp3" data-audio-us-female="/audios/us/run-us-female.mp3"></span>                |
-| <span class="pho">w</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_we_2023feb.mp3"></span>       | **w**e <span class="pho alt">wiː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/we-us-male.mp3" data-audio-us-female="/audios/us/we-us-female.mp3"></span>                   |
-| <span class="pho">j</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/us_phonetics_sound_yes_2023feb.mp3"></span>      | **y**es <span class="pho alt">jes</span><span class="speak-word-inline" data-audio-us-male="/audios/us/yes-us-male.mp3" data-audio-us-female="/audios/us/yes-us-female.mp3"></span>                |
-
-## 1.2.3. 重音符号（Stress symbols）
-
-| Symbols | Functions        | Examples                                                                                                                                                                                             |
-| ------- | ---------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| **ˈ**   | primary stress   | **vi**sion <span class="pho alt">ˈvɪʒən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/vision-us-male.mp3" data-audio-us-female="/audios/us/vision-us-female.mp3"></span>                               |
-| **ˌ**   | secondary stress | **con**troversial <span class="pho alt">ˌkɑːntrəˈvɝːʃəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/controversial-us-male.mp3" data-audio-us-female="/audios/us/controversial-us-female.mp3"></span> |
-
-[^1]: A Github [repo](https://github.com/zelic91/camdict) offers a *JSON* format database of CEPD.
diff --git a/1000-hours/sounds-of-american-english-old/1.3-accents.md b/1000-hours/sounds-of-american-english-old/1.3-accents.md
deleted file mode 100644
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--- a/1000-hours/sounds-of-american-english-old/1.3-accents.md
+++ /dev/null
@@ -1,25 +0,0 @@
-# 1.3. 口音（Accents）
-
-英语也许是地球上地方口音最多的语言，除了英式英语和美式英语之外，还有加拿大英语、澳大利亚英语、苏格兰英语、新西兰英语…… 即便是在英国之内，也有很多不同的口音，甚至伦敦南部和东部的口音都有可能并不相同。同样，在美国，各个区域的口音事实上有很大区别。
-
-English may well be the language with the most regional accents on Earth. It's not just about British English and American English; there's also Canadian English, Australian English, Scottish English, New Zealand English, and so on. Even within the UK, there are countless different accents. You might find that the accent in South London is different from that in East London. Likewise, in the United States, accents can significantly vary depending on the region.
-
-![accents-eight](/images/accents-eight.png)
-
-上图来自于 [www.soundcomparisons.com](https://www.soundcomparisons.com/#/en/Englishes/map/eight/Lgs_Sln) —— 不妨去体会一下同一个英语单词在各地不同的口音……
-
-The image above is from [www.soundcomparisons.com](https://www.soundcomparisons.com/#/en/Englishes/map/eight/Lgs_Sln). Feel free to explore and appreciate how the same English word can sound so different, depending on the regional accent.
-
-[Little Big Shots](https://en.wikipedia.org/wiki/Little_Big_Shots) 节目组曾经请来一位苏格兰小朋友 *Oscar*，听听他是怎么说 *fish* 这个词把主持人差点搞疯的：
-
-<video controls width="720"> <source src="/videos/LittleBigShots-Oscar.mp4" type="video/mp4"></source>Your browser does not support the video tag. </video>
-
-The team behind the show *[Little Big Shots](https://en.wikipedia.org/wiki/Little_Big_Shots)* once invited a Scottish youngster named *Oscar*. Listen to how he pronounces the word *fish* - it nearly drove the host crazy!
-
-事实上，较重的地方口音甚至会令英语母语使用者都束手无策。[这个 Youtube 链接](https://www.youtube.com/watch?v=1jHfY0dDZxA)是 2019 年 10 月英国议会上演的一幕 —— 一位新西兰出生的议员死活听不懂他的苏格兰同事在说什么……
-
-In reality, heavy regional accents can even stump native English speakers. Check out this [YouTube link](https://www.youtube.com/watch?v=1jHfY0dDZxA) for a humorous example. It's a scene from a British Parliament session in October 2019, where a New Zealand-born member couldn't for the life of him understand what his Scottish colleague was saying!
-
-很多人在学英语的时候，对口音的选择异常纠结。其实大可不必，只要想想你最能最常听到的口音是什么就可以了 —— 显然，对绝大多数人来说，在这个视听媒体格外发达的时代，人们更常听到的可能是**美式英语**。
-
-Many people find themselves particularly torn  when deciding on an accent to adopt while learning English. However, it's not as big of a deal as it seems. Simply consider the accent you hear most frequently - it's clear that for the majority of people, in this age where audio and visual media are abundantly prevalent, the *American English* accent is perhaps the one most often heard.
\ No newline at end of file
diff --git a/1000-hours/sounds-of-american-english-old/1.4-articulators.md b/1000-hours/sounds-of-american-english-old/1.4-articulators.md
deleted file mode 100644
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-# 2. 器官（Articulators）
-
-尽管说着不同的语言，人类的大脑构造和发声器官（*articulators*）构造却都是一样的。也正因为如此，所有的人类幼崽都具备习得地球上任何一种语言的潜能 —— 这其实还真是一个颇有些惊人却又常常被忽视的事实。
-
-Despite speaking different languages, humans share the same structure of brain and articulators. It's this commonality that grants every human infants the potential to master any language on Earth - a fascinating yet often overlooked fact.
-
-**说话**对大脑来说是一项异常复杂的活动，大约要它协调差不多 100 块的肌肉才能发出一个音素的声音[^1]。
-
-*Speaking* is an extraordinarily complex activity for the brain, requiring its coordination of nearly 100 muscles just to produce a single phoneme.
-
-<video controls width="720"> <source src="/videos/speech-form-brain-signals.mp4" type="video/mp4"></source>Your browser does not support the video tag. </video>
-
-我们用**嘴**说话…… 更详细地讲，我们说话的时候动用的器官实际上很多，包括但不限于：**下巴**（*lower jaw*）、**嘴唇**（*lips*）、**牙齿**（*teeth*）、**龈脊**（*alveolar ridge*）、**舌尖**（*tongue tip*）、**舌背**（*tongue roof*）、**舌尾**（*back of tongue*）、**软腭**（*soft palate*）、**咽**（*pharynx*）、**喉**（*larynx*）、**声带**（*vocal cords*）等等。
-
-![Speech Tract (zh-CN)](/images/articulators-cn.svg)
-
-We use our *mouths* as a means of communication... To elaborate, when we speak, many parts of our body are actually involved, including but not limited to: *lower jaw* (or mandible), *lips*, *teeth*; *alveolar ridge* (the small bump right behind your upper front teeth); *tongue tip* and *rongue roof* or dorsum; *hard palate* and *soft palate*, and then throat areas which can be further divided into two parts: *pharynx* and *larynx*. Last but not least come your voice makers - *vocal cords.*
-
-![Speech Tract (zh-CN)](/images/articulators-en.svg)
-
-另外一个重要的方面是**呼吸**（*breathe*）—— 也就是说，肺也可以算作是发声器官 —— 呼吸不仅影响声音，也影响节奏；因为换气的必要，自然语流中总是存在**停顿**（*pause*）。
-
-The act of breathing also plays a vital role — in other words, the lungs can also be considered as one of articulators - the breath not only affects speech sound quality but rhythm too due to natural *pauses* for airflow regulation during continuous speech flow.
-
-以下的 X 光视频展示了一个歌手在演唱歌曲时发声器官的活动情况[^2]：
-
-Here's an X-ray video showcasing the movement of a singer's articulators while performing a song:
-
-<video controls width="720"> <source src="/videos/articulator-movement-singing.mp4" type="video/mp4"></source>Your browser does not support the video tag. </video>
-
-说话或者唱歌，形象地来看，很像是口腔体操，锻炼更多的却是大脑内的神经元及其它们之间的连接。
-
-When you think about it, speaking or singing is like oral gymnastics, but the real workout is for the neurons in your brain and the connections among them.
-
-英文**元音发声**时最需要注意的发声器官是**嘴唇**，有两个元音（及其它们各自的长短版本）被称作 *rounded vowels*，<span class="pho">u</span> 和 <span class="pho">ɔ</span>，必须将嘴唇略微凸出并缩成一个小圆形。
-
-When pronouncing English *vowels*, the most critical articulators to pay attention to is *lips*. There are two vowels, along with their long and short versions, known as *rounded vowels*, which are <span class="pho">u</span> and <span class="pho">ɔ</span>. For these, you must slightly protrude your lips and form them into a small circle.
-
-![vowels-mouth-ɔ-u](/images/vowels-mouth-ɔ-u.svg)
-
-而英文**辅音发声时**最需要注意的发声器官之一是**舌头**，很多辅音都需要**舌尖**从**正确的位置**开始发声…… 以下展示的是英文中舌尖最常用的 *4* 个位置：
-
-When pronouncing English *consonants*, one of the most critical articulators is your *tongue*. Many consonants require *the tongue tip* to start making a sound from the *right position*... What follows are the *4* most common positions of the tongue tip in English:
-
-![articulator-tongue-tip-positions](/images/articulator-tongue-tip-positions.svg)
-
-以下表格中舌尖起始位置和辅音的对应会在随后的章节中进一步讲解：
-
-The table below shows the relationship between the initial position of the tongue tip and corresponding consonant sounds. We'll delve deeper into this topic in upcoming sections:
-
-| Positions of tongue tip | Consonants                                      |
-| :---------------------: | :---------------------------------------------- |
-|            ①            | <span class="pho">θ</span>, <span class="pho">ð</span>                                        |
-|            ②            | <span class="pho">s</span>, <span class="pho">z</span>                                        |
-|            ③            | <span class="pho">t</span>, <span class="pho">d</span>, <span class="pho">l</span>, <span class="pho">ʃ</span>, <span class="pho">ʒ</span>, <span class="pho">tʃ</span>, <span class="pho">dʒ</span>, <span class="pho">tr</span>, <span class="pho">dr</span> |
-|            ④            | <span class="pho">r</span>                                             |
-
-[^1]: https://www.youtube.com/watch?v=YHFx6O5x5Hw
-[^2]: https://www.youtube.com/watch?v=2N5q85G3ydk
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diff --git a/1000-hours/sounds-of-american-english-old/2-details.md b/1000-hours/sounds-of-american-english-old/2-details.md
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-# 2. 音素详解
-
-理论上来讲，把每个音素读准本身其实并不难；更何况每种语言都一样，从音素的数量上来看并不是很多，比如英语，总计就那么四十几个而已。
-
-In theory, pronouncing each phoneme correctly isn't really a hard nut to crack; plus, like any other language, English doesn’t have that many of them—just over forty in total.
-
-主要的难点来自于两个方面。
-
-However, there are two main challenges here.
-
-首先是在连贯的自然语音中，几乎每个音素都有这样那样的变化。于是，我们只能通过反复阅读材料，反复练习，反复自我纠正，将起初看起来极为繁杂的知识点逐一突破。
-
-Firstly, almost every single phoneme morphs here and there within fluent speech. So what can one do? The key lies within *repetition* – repeatedly read materials aloud, corrected by self-monitoring your pronunciation, focusing on those pesky shifting details until they become conquered hurdles rather than intimidating obstacles.
-
-更大的困难来自于我们的大脑机制。随着年龄的增加，大脑会过滤母语中用不到的声音，以便提高语音识别的效率 —— 也恰恰是这一点造成了绝大多数成年人学外语的最大障碍。有些声音我们听不到、听不清楚，有些声音听到了却无法分辨，有些声音被我们自己在不知不觉中替换成了另外的样子…… 应对方式只有一个，集中注意力反复听，反复练 —— **注意力集中才是真正的关键**。
-
-An even greater challenge stems from how our brain functions over time: as we age, our minds begin filtering out unnecessary sounds not present in native tongues as noises to enhance linguistic efficiency - which happens also to be a major obstacle for most adults learning foreign languages as some sounds go unheard or indistinct while others get mistakenly replaced unconsciously... The only weapon at hand? Again, *repetition* - repeately listen and practice, with full *attention*, which is another indispensbile key.
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diff --git a/1000-hours/sounds-of-american-english-old/2.1-vowels.md b/1000-hours/sounds-of-american-english-old/2.1-vowels.md
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-# 2.1. 元音（Vowels）
-
-英文总计 6 个基础元音，分别是 <span class="pho">ʌ</span>、<span class="pho">e</span>、<span class="pho">ə</span>、<span class="pho">ɪ</span>、<span class="pho">ʊ</span>、<span class="pho">ɒ</span> —— 这 6 个短元音就好像是 “根” 一样。剩下的十几个元音要么是它们略有变化的更长版本，即，长元音  ——  <span class="pho">ɑː, æ, ɝː,  i, iː, uː, ɔː</span>；要么是它们的组合版本，即，双元音 —— <span class="pho">aɪ, eɪ, ɔɪ, aʊ, oʊ, er, ɪr, ʊr</span>。
-
-In English, there are 6 basic vowels: <span class="pho">ʌ</span>, <span class="pho">e</span>, <span class="pho">ə</span>, <span class="pho">ɪ</span>, <span class="pho">ʊ</span>, and <span class="pho">ɒ</span>. Think of these 6 short vowels like the *roots* of a tree. The remaining more than a dozen vowels are either slightly modified, longer versions of these - the *long* vowels, which are <span class="pho">ɑː, æ, ɝː, i, iː, uː, ɔː</span>; or, they are combinations of these basic sounds, known as *diphthongs* - <span class="pho">aɪ, eɪ, ɔɪ, aʊ, oʊ, er, ɪr, ʊr</span>.
-
-> 在英式英语中，<span class="pho">er, ɪr, ʊr</span> 这 3 个双元音分别读作 <span class="pho">eə, ɪə, ʊə</span>。
->
-> In British English, the diphthongs <span class="pho">er, ɪr, ʊr</span>, which are pronounced respectively as <span class="pho">eər, ɪər, ʊər</span>, are annotated as <span class="pho">eə, ɪə, ʊə</span>.
-
-元音的关键在于它们的**长短**。搞错元音的长短，一方面可能会造成错误或者理解困难。更为重要的是另外一方面 —— 会造成**节奏**（[2.5.4](2.5.4-pace)）混乱。
-
-The crux of vowels lies in their *duration*. If you mess up the length of vowels, not only could it lead to errors or difficulties in understanding, but more importantly, it could disrupt the *rhythm* ([2.5.4](2.5.4-pace)).
-
-由于双元音由两个基础元音构成，所以**双元音**的长度与**长元音**相当。于是，英文**音节**的发声总体上倾向于比其它语言更长，因为 20 多个元音中只有 6 个是短的，与之相对的，剩余 2 倍以上的数量是长的。这是一个相当显著的差异 —— 尤其在与亚洲语言相比的时候尤为明显，因为在大多数亚洲语言中元音（可能被称为韵母、母音）总是等长的，没有长短之分。
-
-Since diphthongs are composed of two basic vowels, their length is equivalent to that of long vowels. As a result, English syllables tend to be pronounced longer overall than in other languages, given that only 6 out of more than 20 vowels are short, while the remaining, more than double in quantity, are long. This is a rather noticeable difference, especially when compared to Asian languages, where vowels always have equal length, with no distinction between *long* and *short*.
-
-另外，美式英语与英式英语有一个显著的不同。英式英语的元音只有长短之分，美式英语里，有些元音是半长元音，比如，<span class="pho">æ</span> 或者 <span class="pho">i</span>。
-
-On the other hand, there's a notable difference between American and British English when it comes to vowel duration. In British English, vowels are either long or short. On the other hand, in American English, some vowels fall into a category of semi-long vowels, such as <span class="pho">æ</span> or <span class="pho">i</span>.
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diff --git a/1000-hours/sounds-of-american-english-old/2.1.1-lips.md b/1000-hours/sounds-of-american-english-old/2.1.1-lips.md
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-# 2.1.1. 口型（Mouth shape）
-
-元音发声时，气流从肺部通过声门冲击**声带**，使其均匀振动，而后通过起着共鸣器作用的口腔，无阻力地呼出。
-
-For vowel pronunciation, the airflow from your lungs strikes against your *vocal cords* through the glottis. This produces a consistent vibration that is amplified as it travels unimpeded through your mouth - the resonator cavity - before being expelled freely.
-
-生成不同元音的主要器官是嘴唇，这也是婴幼儿在学说话时所能观察到的唯一发声器官。张嘴的另外一个器官是下巴，下巴拉开，口型变大。
-
-Notably, a prime organ involved here: lips - the only visible speech articulator observable when infants are learning to speak. Another organ that opens the mouth is the jaw, which, when pulled apart, enlarges the shape of the mouth.
-
-以下是  5 个基础元音发声时的口型（嘴唇位置）：
-
-Here are the mouth shapes (or, lips positions) during enunciation of five basic vowels:
-
-![Vowels mouth shape](/images/vowels-mouth-shape.svg)
-
-当然，除了嘴唇的形状之外，影响元音发声的器官还有舌面的位置、软腭的动作 —— 影响口腔内气流共振的空间 —— 不过，由于人类语言的相通属性，人们在这些基础元音的发声上都没有任何困难。
-
-Certainly, besides the mouth, other articulators influencing vowel pronunciation include where tongue lies and what's happening with soft palate, forming  a specific space that affects the resonance of airflow in the mouth. But thanks to universal linguistic attributes in humans, no one really struggles when it comes down to these basic vowels.
-
-另外，英文的 <span class="pho">ə</span> 口型与 <span class="pho">e</span> 接近；而 <span class="pho">æ</span> 的口型比 <span class="pho">e</span> 的大一点、比 <span class="pho">ɑ</span> 的小一点。
-
-Moreover, regarding English phonetics: the mouth shape for <span class="pho">ə</span> is similar to that for <span class="pho">e</span>, whereas for <span class="pho">æ</span>, a slightly larger opening is formed than when saying <span class="pho">e</span>, but smaller one compared with pronouncing <span class="pho">ɑ</span>.
diff --git a/1000-hours/sounds-of-american-english-old/2.1.10-ɤ.md b/1000-hours/sounds-of-american-english-old/2.1.10-ɤ.md
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-# 2.1.10. <span class="pho">ɤ</span>
-
-人类的语音在最底层是相通的 —— 最明显的例证就是所有的语言都一样，不仅都以元音为核心，并且，都有大致相同的基础元音音素，比如 <span class="pho">ɑ</span>、<span class="pho">i</span>、<span class="pho">ʊ</span>、<span class="pho">e</span>、<span class="pho">ɔ</span>…… 日文就恰好只有这五个母音。英文还另外有一个 <span class="pho">ə</span>；而韩文比英文还要多出一个 <span class="pho">ɤ</span><span class="speak-word-inline" data-audio-other="/audios/us/Close-mid_back_unrounded_vowel.ogg.mp3"></span>（韩文字符为 <span class="pho">ᅳ</span>） —— 这个音中文也有，比如，在 “思念” 这个词中， “思”（<span class="pho">sī</span>）的韵母就是这个音。
-
-Human speech, at its core, is universal - the clearest example being that all languages share certain fundamental tenets. Every language places vowels at their heart and maintains a similar basic vowel phonemes such as <span class="pho">ɑ</span>, <span class="pho">i</span>, <span class="pho">ʊ</span>, <span class="pho">e</span>, <span class="pho">ɔ</span>, amongst others. Take Japanese for instance; it uses precisely these five vowels only. English includes one more: <span class="pho">ə</span>. Korean even outpaces English by adding another one —<span class="pho">ɤ</span><span class="speak-word-inline" data-audio-other="/audios/us/Close-mid_back_unrounded_vowel.ogg.mp3"></span> (represented in Hangul as <span class="pho">ᅳ</span>). Interestingly enough you can find this sound in Mandarin Chinese too — like in <span class="pho">sī</span> of "思念" <span class="pho">sīniàn</span>, meaning to miss or remember.
-
-虽然英文的音标列表里并没有收录 <span class="pho">ɤ</span> 这个音，可实际上，你试试就知道了：<span class="pho">d</span> 被读作 <span class="pho">dɤ</span>，<span class="pho">g</span> 被读作 <span class="pho">gɤ</span> —— 其中的 <span class="pho">ɤ</span> 很轻很短；同样，<span class="pho">t</span> 实际上被读作 <span class="pho">tɤ</span>，<span class="pho">k</span> 被读作 <span class="pho">kɤ</span> —— 其中的 <span class="pho">ɤ</span> 没有气流振动。
-
-Even though the phonetic symbol <span class="pho">ɤ</span> isn't included in English phonetic chart, you'll notice something interesting if you try it out: the letter <span class="pho">d</span> is actually pronounced as <span class="pho">dɤ</span>, and <span class="pho">g</span> is pronounced as <span class="pho">gɤ</span>. Here, the <span class="pho">ɤ</span> sound is very light and brief. Similarly, <span class="pho">t</span> is actually pronounced as <span class="pho">tɤ</span>, and <span class="pho">k</span> is pronounced as <span class="pho">kɤ</span>, with the <span class="pho">ɤ</span> not involving any airflow vibration.
-
-之前讲过，非重音音节里的元音可能会被弱化为 *schwa*（[2.1.5-ə](2.1.5-ə)）<span class="pho">ə</span>…… 在自然语流中，连 *schwa* <span class="pho">ə</span> 都可能会被进一步弱化,变成非常轻的 <span class="pho">ɤ</span>。比如，常用词 *reasonable*，字典里标注的当然是 <span class="pho alt">ˈriːzənəbəl</span>，实际听到的常常是 <span class="pho alt">ˈriːzɤnəbəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/reasonable-us-male.mp3" data-audio-us-female="/audios/us/reasonable-us-female.mp3"></span> —— "*so*" 这个音节的发音不是 <span class="pho alt">zə</span>，而是 <span class="pho alt">zɤ</span> 甚至 <span class="pho alt">z</span>……
-
-Previously, we discussed that vowels in unstressed syllables might be reduced to a *schwa* <span class="pho">ə</span> ([2.1.5-ə](2.1.5-ə)). In natural speech, even the *schwa* <span class="pho">ə</span> can be further weakened to a very light <span class="pho">ɤ</span>. For example, take the common word *reasonable*. The dictionary may mark it as <span class="pho alt">ˈriːzənəbəl</span>, but in real-life conversations, you often hear it pronounced as <span class="pho alt">ˈriːzɤnəbəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/reasonable-us-male.mp3" data-audio-us-female="/audios/us/reasonable-us-female.mp3"></span>. This means the syllable "*so*" sounds more like <span class="pho alt">zɤ</span> or even <span class="pho alt">z</span>, rather than <span class="pho alt">zə</span>.
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diff --git a/1000-hours/sounds-of-american-english-old/2.1.2-tongue.md b/1000-hours/sounds-of-american-english-old/2.1.2-tongue.md
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-# 2.1.2. 舌位（Tongue Positions）
-
-元音发声时舌身的位置很重要。以下展示的是每个元音发声时对应的舌身位置。我们靠移动下巴控制口型的大小，下巴张开得越大，舌身位置相对越低，同时舌身位置也越靠后[^1]。
-
-The position of your tongue is crucial when pronouncing vowels. The following shows the corresponding tongue position for each vowel sound. We control the shape of our mouth by moving our jaw. The wider we open our jaw, the lower and further back the tongue position will be.
-
-![tongue-positions-of-vowels](/images/tongue-positions-of-vowels.svg)
-
-舌身的位置决定口腔内气流共振空间的大小，进而可以配合不同的唇形发出不同的元音。
-
-The position of your tongue in your mouth determines the size of the resonance space for airflow, which, when paired with different mouth shapes, produces various vowel sounds.
-
-虽然舌身位置很重要，但 “控制舌身位置” 对绝大多数人来说并不现实 —— 你试试就知道了。
-
-While the position of the vocal cords is crucial, trying to consciously control it isn't realistic for most people - just give it a go and you'll see.
-
-以下是朗读一些单词的时候发声器官活动情况的 3D 展示[^2]，可以格外注意一下舌身的位置变动：
-
-Here's a 3D illustration showcasing the activity of articulators when pronouncing certain words, please pay special attention to changes of the tongue positions:
-
-<video controls width="720"> <source src="/videos/3d-presentation.mp4" type="video/mp4"></source>Your browser does not support the video tag. </video>
-
-幸运的是，练习美式发音的时候，只有一种情况需要我们主动控制舌身位置并专门练习 —— <span class="pho">ə</span> 的儿化音（<span class="pho">ɚ</span> 和 <span class="pho">ɝː</span>），参见 [2.1.5](2.1.5-ə)。
-
-Fortunately, when practicing American pronunciation, there's only one situation where we need to actively control and practice the position of the vocal cords - the r-colored vowel sound in <span class="pho">ə</span> (represented as <span class="pho">ɚ</span> and <span class="pho">ɝː</span>). Please refer to section [2.1.5](2.1.5-ə) for more information.
-
-另外，iOS 上有一个 APP，[The Phonetics 3D](https://apps.apple.com/us/app/the-phonetics-3d/id841485989)，一个日本人做的软件，$7.99 的价格，可以看到每个单词朗读时口腔内部的活动情况，很是实用：
-
-Additionally, there's an app on iOS called [The Phonetics 3D](https://apps.apple.com/us/app/the-phonetics-3d/id841485989), created by a Japanese developer, priced at $7.99, and it allows you to see the movements inside the mouth when pronouncing each word, being extremely helpful.
-
-<video controls width="720"> <source src="/videos/literally.mp4" type="video/mp4"></source>Your browser does not support the video tag. </video>
-
-[^1]: Figure adapted from *FUNDAMENTALS OF PHONETICS: a practical guide for students* 5th Edition, by Larry H. Small, 2019. Page 55
-[^2]: https://www.youtube.com/watch?v=wYwk07QM4rc
\ No newline at end of file
diff --git a/1000-hours/sounds-of-american-english-old/2.1.3-ʌ.md b/1000-hours/sounds-of-american-english-old/2.1.3-ʌ.md
deleted file mode 100644
index 5596182d..00000000
--- a/1000-hours/sounds-of-american-english-old/2.1.3-ʌ.md
+++ /dev/null
@@ -1,85 +0,0 @@
-# 2.1.3. <span class="pho">ʌ/ɑː/aːr</span>
-
-从唇形上来看，<span class="pho">ʌ</span> 的唇形最小，<span class="pho">ɑːr</span> 的唇形最大。
-
-In terms of mouth shape, the vowel sound <span class="pho">ʌ</span> requires the lips to be the most closed, while the vowel sound <span class="pho">ɑːr</span> requires the lips to be the most open.
-
-![mouth shape of ʌ/ɑ](/images/vowels-mouth-ʌ-ɑ.svg)
-
-美音的 <span class="pho">ʌ</span> 实际上非常接近于英音的 <span class="pho">ə</span>，比如，*but* <span class="pho alt">bʌt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/but-us-male.mp3" data-audio-us-female="/audios/us/but-us-female.mp3"></span>听起来更接近于 <span class="pho alt">bət</span>。
-
-The American pronunciation of <span class="pho">ʌ</span> is actually quite similar to <span class="pho">ə</span>. For instance, the word *but*, pronounced <span class="pho alt">bʌt</span>, often sounds more like <span class="pho alt">bət</span>.
-
-美国人还会再进一步，会把很多**非重读音节**内的元音简化为 <span class="pho">ə</span> —— 对此还有个专门的术语，将其称为 *schwa*。所以，*encourage* 这个词英国人和美国人读得不太一样，英国人会读作 <span class="pho alt">ɪnˈkʌrɪdʒ</span><span class="speak-word-inline" data-audio-uk-male="/audios/us/encourage-uk-male.mp3" data-audio-uk-female="/audios/us/encourage-uk-female.mp3"></span>，但，美国人却将其被读成 <span class="pho alt">ɪnˈkɝːədʒ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/encourage-us-male.mp3" data-audio-us-female="/audios/us/encourage-us-female.mp3"></span>—— 不仅要将 <span class="pho">ʌ</span> 读成 <span class="pho">ɝː</span>（长元音），还要将 <span class="pho">ɪ</span> 变成 *schwa*, <span class="pho">ə</span>……
-
-They even go a step further, simplifying many *unstressed vowel sounds* to <span class="pho">ə</span>, which is particularly referred to as a *schwa*. So, the word *encourage* is pronounced differently by Brits and Americans. Brits say <span class="pho alt">ɪnˈkʌrɪdʒ</span><span class="speak-word-inline" data-audio-uk-male="/audios/us/encourage-uk-male.mp3" data-audio-uk-female="/audios/us/encourage-uk-female.mp3"></span>, while Americans pronounce it as <span class="pho alt">ɪnˈkɝːədʒ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/encourage-us-male.mp3" data-audio-us-female="/audios/us/encourage-us-female.mp3"></span>. In this case, not only is <span class="pho">ʌ</span> pronounced as <span class="pho">ə</span>, but the <span class="pho">ɪ</span> also turns into a *schwa*, <span class="pho">ə</span>...
-
-在美式英语中，<span class="pho">ɑː</span> 常常会被儿化 —— 加上一个卷舌音 <span class="pho">r</span>，所以很多美式词典干脆用 <span class="pho">ɑr</span> 标注。比如，*card* <span class="pho alt">kɑːrd</span><span class="speak-word-inline" data-audio-us-male="/audios/us/card-us-male.mp3" data-audio-us-female="/audios/us/card-us-female.mp3"></span>, *mark* <span class="pho alt">mɑːrk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/mark-us-male.mp3" data-audio-us-female="/audios/us/mark-us-female.mp3"></span>。
-
-The vowel <span class="pho">ɑː</span> is often *rhotacized* - meaning it is followed by a <span class="pho">r</span> sound, which leads to many American Dictionaries replacing <span class="pho">ɑː</span> with <span class="pho">ɑr</span>. For example, *card* is pronounced as <span class="pho alt">kɑːrd</span><span class="speak-word-inline" data-audio-us-male="/audios/us/card-us-male.mp3" data-audio-us-female="/audios/us/card-us-female.mp3"></span>, and *mark* as <span class="pho alt">mɑːrk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/mark-us-male.mp3" data-audio-us-female="/audios/us/mark-us-female.mp3"></span>.
-
-英音中的短元音 <span class="pho">ɒ</span>，在美音中读作 <span class="pho">ɑː</span>。比如，*hot*, 英音是 <span class="pho alt">hɒt</span><span class="speak-word-inline" data-audio-uk-male="/audios/us/hot-uk-male.mp3" data-audio-uk-female="/audios/us/hot-uk-female.mp3"></span>，美音是 <span class="pho alt">hɑːt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/hot-us-male.mp3" data-audio-us-female="/audios/us/hot-us-female.mp3"></span>。
-
-The short vowel <span class="pho">ɒ</span> in British English, is pronounced as <span class="pho">ɑː</span>. For instance, the word *hot* is pronounced <span class="pho alt">hɒt</span><span class="speak-word-inline" data-audio-uk-male="/audios/us/hot-uk-male.mp3" data-audio-uk-female="/audios/us/hot-uk-female.mp3"></span>in British English and <span class="pho alt">hɑːt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/hot-us-male.mp3" data-audio-us-female="/audios/us/hot-us-female.mp3"></span>in American English.
-
-请注意，在 CEPD 中，对应着英音 <span class="pho">ɒ</span> 的美音 <span class="pho">ɑː</span> 虽然带着一个长元音符号，它实际的长度相当于**半长元音**，即，它比短元音长一些，比长元音短一些。除了 CEPD 之外，大多词典会把 *hot* 的音标标注为 <span class="pho alt">hɑt</span> —— 即，没有长元音符号。按照 CEPD 的标注，可以这么理解：在美式英语中，<span class="pho">ʌ</span> 最短，<span class="pho">ɑː</span> 更长一些，而 <span class="pho">ɑːr</span> 最长。
-
-Please note that in CEPD, the American English sound <span class="pho">ɑː</span>, corresponding to the British <span class="pho">ɒ</span>, is denoted with a long vowel symbol. However, its actual duration is akin to a **semi-long vowel** - slightly longer than a short vowel but shorter than a long vowel. Apart from CEPD, most dictionaries would transcribe *hot* as <span class="pho alt">/hɑt/</span>, without the long vowel symbol. In accordance with CEPD's notation, you can understand it this way: in American English, <span class="pho">ʌ</span> is the shortest, <span class="pho">ɑː</span> is a bit longer, and <span class="pho">ɑːr`</span> is the longest.
-
-英音中的 <span class="pho">ɑː</span> 在美式英语中读作 <span class="pho">æ</span>，最常见的例子是 *ask*，英音是 <span class="pho alt">ɑːsk</span><span class="speak-word-inline" data-audio-uk-male="/audios/us/ask-uk-male.mp3" data-audio-uk-female="/audios/us/ask-uk-female.mp3"></span>，美音是 <span class="pho alt">æsk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/ask-us-male.mp3" data-audio-us-female="/audios/us/ask-us-female.mp3"></span>。
-
-In American English, the British <span class="pho">ɑː</span> sound is pronounced as <span class="pho">æ</span>. The most common example is the word *ask*. In British English, it's pronounced as <span class="pho alt">ɑːsk</span><span class="speak-word-inline" data-audio-uk-male="/audios/us/ask-uk-male.mp3" data-audio-uk-female="/audios/us/ask-uk-female.mp3"></span>, while in American English, it's pronounced as <span class="pho alt">æsk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/ask-us-male.mp3" data-audio-us-female="/audios/us/ask-us-female.mp3"></span>.
-
-## 拼写（Spellings）
-
-### <span class="pho">ʌ</span>
-
-* **u**
-  * sun <span class="pho alt">sʌn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sun-us-male.mp3" data-audio-us-female="/audios/us/sun-us-female.mp3"></span>
-  * cup <span class="pho alt">kʌp</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/cup-us-male.mp3" data-audio-us-female="/audios/us/cup-us-female.mp3"></span>
-  * but <span class="pho alt">bʌt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/but-us-male.mp3" data-audio-us-female="/audios/us/but-us-female.mp3"></span>
-* **o**
-  * son <span class="pho alt">sʌn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/son-us-male.mp3" data-audio-us-female="/audios/us/son-us-female.mp3"></span>
-  * comfort <span class="pho alt">ˈkʌm.fɚt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/comfort-us-male.mp3" data-audio-us-female="/audios/us/comfort-us-female.mp3"></span>
-  * money <span class="pho alt">ˈmʌn.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/money-us-male.mp3" data-audio-us-female="/audios/us/money-us-female.mp3"></span>
-* **ou**
-  * young <span class="pho alt">jʌŋ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/young-us-male.mp3" data-audio-us-female="/audios/us/young-us-female.mp3"></span>
-  * double <span class="pho alt">ˈdʌb.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/double-us-male.mp3" data-audio-us-female="/audios/us/double-us-female.mp3"></span>
-  * country <span class="pho alt">ˈkʌn.tri</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/country-us-male.mp3" data-audio-us-female="/audios/us/country-us-female.mp3"></span>
-* **oo**
-  * blood <span class="pho alt">blʌd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/blood-us-male.mp3" data-audio-us-female="/audios/us/blood-us-female.mp3"></span>
-  * flood <span class="pho alt">flʌd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/flood-us-male.mp3" data-audio-us-female="/audios/us/flood-us-female.mp3"></span>
-
-### <span class="pho">ɑː</span> (equivalent to British <span class="pho">ɒ</span>)
-
-* **a**
-  * father <span class="pho alt">ˈfɑː.ðɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/father-us-male.mp3" data-audio-us-female="/audios/us/father-us-female.mp3"></span>
-  * watch <span class="pho alt">wɑːtʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/watch-us-male.mp3" data-audio-us-female="/audios/us/watch-us-female.mp3"></span>
-  * wasp <span class="pho alt">wɑːsp</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/wasp-us-male.mp3" data-audio-us-female="/audios/us/wasp-us-female.mp3"></span>
-* **al**
-  * almond <span class="pho alt">ˈɑːl.mənd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/almond-us-male.mp3" data-audio-us-female="/audios/us/almond-us-female.mp3"></span>
-  * balm <span class="pho alt">bɑːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/balm-us-male.mp3" data-audio-us-female="/audios/us/balm-us-female.mp3"></span>
-  * palm <span class="pho alt">pɑːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/palm-us-male.mp3" data-audio-us-female="/audios/us/palm-us-female.mp3"></span>
-* **au**
-  * because <span class="pho alt">bɪˈkɑːz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/because-us-male.mp3" data-audio-us-female="/audios/us/because-us-female.mp3"></span>
-  * clause <span class="pho alt">klɑːz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/clause-us-male.mp3" data-audio-us-female="/audios/us/clause-us-female.mp3"></span>
-  * paunch <span class="pho alt">pɑːntʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/paunch-us-male.mp3" data-audio-us-female="/audios/us/paunch-us-female.mp3"></span>
-* **aw**
-  * drawn <span class="pho alt">drɑːn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/drawn-us-male.mp3" data-audio-us-female="/audios/us/drawn-us-female.mp3"></span>
-  * awning <span class="pho alt">ˈɑː.nɪŋ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/awning-us-male.mp3" data-audio-us-female="/audios/us/awning-us-female.mp3"></span>
-  * law <span class="pho alt">lɑː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/law-us-male.mp3" data-audio-us-female="/audios/us/law-us-female.mp3"></span>
-* **o**
-  * hot <span class="pho alt">hɑːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/hot-us-male.mp3" data-audio-us-female="/audios/us/hot-us-female.mp3"></span>
-  * dog <span class="pho alt">dɑːɡ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/dog-us-male.mp3" data-audio-us-female="/audios/us/dog-us-female.mp3"></span>
-  * log <span class="pho alt">lɑːɡ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/log-us-male.mp3" data-audio-us-female="/audios/us/log-us-female.mp3"></span>
-* **ough**
-  * bought <span class="pho alt">bɑːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bought-us-male.mp3" data-audio-us-female="/audios/us/bought-us-female.mp3"></span>
-  * thought <span class="pho alt">θɑːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/thought-us-male.mp3" data-audio-us-female="/audios/us/thought-us-female.mp3"></span>
-  * fought <span class="pho alt">fɑːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/fought-us-male.mp3" data-audio-us-female="/audios/us/fought-us-female.mp3"></span>
-
-### <span class="pho">ɑːr</span>
-
-* **ar**
-  * car <span class="pho alt">kɑːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/car-us-male.mp3" data-audio-us-female="/audios/us/car-us-female.mp3"></span>
-  * far <span class="pho alt">fɑːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/far-us-male.mp3" data-audio-us-female="/audios/us/far-us-female.mp3"></span>
-  * start <span class="pho alt">stɑːrt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/start-us-male.mp3" data-audio-us-female="/audios/us/start-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.1.4-e.md b/1000-hours/sounds-of-american-english-old/2.1.4-e.md
deleted file mode 100644
index 380a2e22..00000000
--- a/1000-hours/sounds-of-american-english-old/2.1.4-e.md
+++ /dev/null
@@ -1,66 +0,0 @@
-# 2.1.4. <span class="pho">e</span>/<span class="pho">æ</span>
-
-有些词典，针对美式发音，常常会用 <span class="pho">ɛ</span> 标注 <span class="pho">e</span> 这个音[^1]。
-
-Some dictionaries often use <span class="pho">ɛ</span> to annotate the American English sound of <span class="pho">e</span>.
-
-<span class="pho">æ</span> 相当于是 <span class="pho">e</span> 的更长版本。虽然 <span class="pho">æ</span> 后面没有长元音符号 <span class="pho">ː</span>，但它的确比其它短元音**长**，算作**半长元音**。
-
-<span class="pho">æ</span> can be deemed as a more extended version of <span class="pho">e</span>. Even though there's no long vowel symbol <span class="pho">ː</span> following <span class="pho">æ</span>, it is *longer* than other short vowels, and is a *semi-long vowel*.
-
-![mouth shape e-æ](/images/vowels-mouth-e-æ.svg)
-
-亚洲人在读这个音的时候，经过提醒，都能做到把嘴巴张得相对更大一点，但都会不由自主地将它读成更短的版本。
-
-When Asians try to pronounce this sound, once reminded, they can usually open their mouths a bit wider, but they often unconsciously make the sound shorter than it should be.
-
-<span class="pho">æ</span> 的发音有两个要点:
-
-> 1. 音拉长一点
-> 2. 嘴张大一点
-
-There are two key points to pronouncing <span class="pho">æ</span>:
-
-> 1. Stretch the sound a little longer
-> 2. Open your mouth wider
-
-其中，第一个要点相对更为重要。你可以多试试这两个词，*apple* <span class="pho alt">ˈæpəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/apple-us-male.mp3" data-audio-us-female="/audios/us/apple-us-female.mp3"></span>，*banana* <span class="pho alt">bəˈnænə</span><span class="speak-word-inline" data-audio-us-male="/audios/us/banana-us-male.mp3" data-audio-us-female="/audios/us/banana-us-female.mp3"></span>，并刻意把其中的 <span class="pho">æ</span> 拉得更长一点。
-
-The first point is relatively more important. Try saying these two words: *apple* <span class="pho alt">ˈæpəl</span> and *banana* <span class="pho alt">bəˈnænə</span>, and try intentionally stretching the <span class="pho">æ</span> a little longer.
-
-[^1]: In IPA, <span class="pho">e</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Close-mid_front_unrounded_vowel.ogg.mp3"></span> is actually pronounced more like <span class="pho">eɪ</span>, a front, closed, unrounded vowel, while <span class="pho">e</span> in CEPD is equivalent to <span class="pho">ɛ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Open-mid_front_unrounded_vowel.ogg.mp3"></span> in IPA, a front, open-mid, unrounded vowel.
-
-## 拼写（Spellings）
-
-### <span class="pho">e</span>
-
-* **e**
-  * bed <span class="pho alt">bed</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bed-us-male.mp3" data-audio-us-female="/audios/us/bed-us-female.mp3"></span>
-  * guess <span class="pho alt">ɡes</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/guess-us-male.mp3" data-audio-us-female="/audios/us/guess-us-female.mp3"></span>
-  * pet <span class="pho alt">pet</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pet-us-male.mp3" data-audio-us-female="/audios/us/pet-us-female.mp3"></span>
-* **ea**
-  * bread <span class="pho alt">bred</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bread-us-male.mp3" data-audio-us-female="/audios/us/bread-us-female.mp3"></span>
-  * dead <span class="pho alt">ded</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/dead-us-male.mp3" data-audio-us-female="/audios/us/dead-us-female.mp3"></span>
-  * lead <span class="pho alt">liːd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/lead-us-male.mp3" data-audio-us-female="/audios/us/lead-us-female.mp3"></span>
-* **a**
-  * any <span class="pho alt">ˈen.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/any-us-male.mp3" data-audio-us-female="/audios/us/any-us-female.mp3"></span>
-  * many <span class="pho alt">ˈmen.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/many-us-male.mp3" data-audio-us-female="/audios/us/many-us-female.mp3"></span>
-  * says <span class="pho alt">sez</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/says-us-male.mp3" data-audio-us-female="/audios/us/says-us-female.mp3"></span>
-* **ai**
-  * again <span class="pho alt">əˈɡen</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/again-us-male.mp3" data-audio-us-female="/audios/us/again-us-female.mp3"></span>
-  * said <span class="pho alt">sed</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/said-us-male.mp3" data-audio-us-female="/audios/us/said-us-female.mp3"></span>
-* **ie**
-  * friend <span class="pho alt">frend</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/friend-us-male.mp3" data-audio-us-female="/audios/us/friend-us-female.mp3"></span>
-
-### <span class="pho">æ</span>
-
-* **a**
-  * apple <span class="pho alt">ˈæp.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/apple-us-male.mp3" data-audio-us-female="/audios/us/apple-us-female.mp3"></span>
-  * cat <span class="pho alt">kæt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/cat-us-male.mp3" data-audio-us-female="/audios/us/cat-us-female.mp3"></span>
-  * glass <span class="pho alt">ɡlæs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/glass-us-male.mp3" data-audio-us-female="/audios/us/glass-us-female.mp3"></span>
-* **al**
-  * calf <span class="pho alt">kæf</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/calf-us-male.mp3" data-audio-us-female="/audios/us/calf-us-female.mp3"></span>
-  * half <span class="pho alt">hæf</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/half-us-male.mp3" data-audio-us-female="/audios/us/half-us-female.mp3"></span>
-* **au**
-  * laugh <span class="pho alt">læf</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/laugh-us-male.mp3" data-audio-us-female="/audios/us/laugh-us-female.mp3"></span>
-  * draught <span class="pho alt">dræft</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/draught-us-male.mp3" data-audio-us-female="/audios/us/draught-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.1.5-ə.md b/1000-hours/sounds-of-american-english-old/2.1.5-ə.md
deleted file mode 100644
index 88a753bf..00000000
--- a/1000-hours/sounds-of-american-english-old/2.1.5-ə.md
+++ /dev/null
@@ -1,114 +0,0 @@
-# 2.1.5. <span class="pho">ə</span>/<span class="pho">ɚ</span>/<span class="pho">ɝː</span>
-
-<span class="pho">ə</span> 在美式英语中有三个版本，非重读音节央元音 <span class="pho">ə</span>（schwa），儿化短元音 <span class="pho">ɚ</span> 和儿化长元音 <span class="pho">ɝː</span>。
-
-In American English, there are three versions of the sound <span class="pho">ə</span>, including the schwa <span class="pho">ə</span>, which is used in unstressed syllables, the rhotacized short vowel <span class="pho">ɚ</span>, and the rhotacized long vowel <span class="pho">ɝː</span>.
-
-初学者容易矫枉过正，遇到所有的 <span class="pho">ə</span> 都要读成儿化音…… 比如，可能会把 *focus* <span class="pho alt">ˈfoʊkəs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/focus-us-male.mp3" data-audio-us-female="/audios/us/focus-us-female.mp3"></span> 错读成 <span class="pho alt">ˈfoʊkɚs</span><span class="speak-word-inline" data-audio-other="/audios/us/focurs-us.mp3"></span>。
-
-Beginners tend to overdo it and add a <span class="pho">r</span> whenever they encounter these sounds, for example, mispronouncing *focus* <span class="pho alt">ˈfoʊkəs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/focus-us-male.mp3" data-audio-us-female="/audios/us/focus-us-female.mp3"></span> as <span class="pho alt">ˈfoʊkɚs</span><span class="speak-word-inline" data-audio-other="/audios/us/focurs-us.mp3"></span>.
-
-<span class="pho">ɚ</span> 和 <span class="pho">ɝː</span> 这两个儿化音，有两种发声方式，一种是凭直觉卷起舌尖（无论是前卷还是后卷，都被称作 *Retroflex R*），这也是绝大多数初学者发这个音的唯一选择。
-
-The rhotacized <span class="pho">ɚ</span> and <span class="pho">ɝː</span> sounds, can be produced in two different ways. Most beginners instinctively curl their tongue tip (where forward or backword) to produce this sound, which is called *Retroflex R*, as it's generally the only method they're familiar with.
-
-由于这个音发声时的舌头动作是别人看不见的，所以，人们在学这个发音的时候，无法猜到第二种方式（被称作 *Bunched R*）：舌尾部分抬起来，略微后缩，使舌的两侧接触到后牙。舌尾的中心部分较低，空气通过这个凹槽产生声音。
-
-Since the tongue's movements are invisible during speech, it's difficult for learners to guess the second method, called *Bunched R*, which involves lifting the back part of the tongue, pulling it back a bit, and allowing the sides of the tongue to touch the back teeth. The center of the tongue's rear is slightly lowered, creating a groove for the air to pass through and generate the sound.
-
-![articulator-tongue-tip-ɚ](/images/articulator-tongue-tip-ɚ.svg)
-
-以下是另外一个角度的图示[^1]：
-
-Here's another illustration from different perspective[^1]:
-
-![retroflex-bunched-r](/images/retroflex-bunched-r.svg)
-
-事实上，其他的儿化音也都可以用这种方式发声。不妨用这种方式重新试试 *card* <span class="pho alt">kɑːrd</span><span class="speak-word-inline" data-audio-us-male="/audios/us/card-us-male.mp3" data-audio-us-female="/audios/us/card-us-female.mp3"></span>, *mark* <span class="pho alt">mɑːrk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/mark-us-male.mp3" data-audio-us-female="/audios/us/mark-us-female.mp3"></span>；再试试 *door* <span class="pho alt">dɔːr</span><span class="speak-word-inline" data-audio-us-male="/audios/us/door-us-male.mp3" data-audio-us-female="/audios/us/door-us-female.mp3"></span>, *short* <span class="pho alt">ʃɔːrt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/short-us-male.mp3" data-audio-us-female="/audios/us/short-us-female.mp3"></span>, *poor* <span class="pho alt">pʊr</span><span class="speak-word-inline" data-audio-us-male="/audios/us/poor-us-male.mp3" data-audio-us-female="/audios/us/poor-us-female.mp3"></span>, *your* <span class="pho alt">jʊr</span><span class="speak-word-inline" data-audio-us-male="/audios/us/your-us-male.mp3" data-audio-us-female="/audios/us/your-us-female.mp3"></span>…… 试过之后，再进行比较，你会发现更多的时候，第二种方式比第一种方式更方便。
-
-In fact, you can use this method to pronounce other rhotacized vowels as well. Give it a shot with words like *card* <span class="pho alt">kɑːrd</span><span class="speak-word-inline" data-audio-us-male="/audios/us/card-us-male.mp3" data-audio-us-female="/audios/us/card-us-female.mp3"></span> and *mark* <span class="pho alt">mɑːrk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/mark-us-male.mp3" data-audio-us-female="/audios/us/mark-us-female.mp3"></span> again; and then try it out with *door* <span class="pho alt">dɔːr</span><span class="speak-word-inline" data-audio-us-male="/audios/us/door-us-male.mp3" data-audio-us-female="/audios/us/door-us-female.mp3"></span>, *short* <span class="pho alt">ʃɔːrt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/short-us-male.mp3" data-audio-us-female="/audios/us/short-us-female.mp3"></span>, *poor* <span class="pho alt">pʊr</span><span class="speak-word-inline" data-audio-us-male="/audios/us/poor-us-male.mp3" data-audio-us-female="/audios/us/poor-us-female.mp3"></span>, and *your* <span class="pho alt">jʊr</span><span class="speak-word-inline" data-audio-us-male="/audios/us/your-us-male.mp3" data-audio-us-female="/audios/us/your-us-female.mp3"></span>... After giving it a try, you'll notice that more often than not, the second method is more convenient than the first.
-
-在美式英语中，人们在说儿化音的时候，使用第二种方式（*Bunched R*）更多。即便是使用第一种方式（*Retroflex R*），舌尖无论是前卷还是后卷，都一样，绝不会贴到龈脊上。
-
-In American English, more often than not, people prefer using the second method (*Bunched R*) when making the rhotacized sound. Even if they use the first method (*Retroflex R*), the tip of the tongue, whether curled forward or backward, **never** touch the *alveolar ridge* behind the teeth.
-
-另外，辅音 <span class="pho">ʃ/ʒ</span>、<span class="pho">tʃ/dʒ</span> 在发音的时候，舌尾也是同样的位置。
-
-Moreover, when pronouncing the consonants <span class="pho">ʃ/ʒ</span> ([2.2.8](2.2.8-ʃʒ)) and <span class="pho">tʃ/dʒ</span> ([2.2.10](2.2.10-tʃdʒ)), the position of the back part of the tongue is the same.
-
-注意，在连贯的自然语音中，很多非重音音节的元音，都有被简化成 <span class="pho">ə</span>（*schwa*）的倾向，尤其是 <span class="pho">ɪ</span>。比如，*individual*, <span class="pho alt">ˌɪndəˈvɪdʒuəl</span>，实际上会被读作 <span class="pho">ˌɪndəˈvɪdʒəʷəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/individual-us-male.mp3" data-audio-us-female="/audios/us/individual-us-female.mp3"></span> —— <span class="pho">u</span> 也变成了 <span class="pho">ə</span>，而后 <span class="pho">u</span> 和 <span class="pho">ə</span> 之间有个加音 <span class="pho">ʷ</span>…… 事实上，现在已经有很多词典干脆直接标注成了后者。
-
-Keep in mind that in fluent, natural speech, many unstressed vowel sounds in syllables are often simplified to <span class="pho">ə</span> (*schwa*), especially <span class="pho">ɪ</span>. For instance, *individual*  <span class="pho alt">ˌɪndɪˈvɪdʒjʊəl</span>, is often actually pronounced as <span class="pho alt">ˌɪndəˈvɪdʒəʷəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/individual-us-male.mp3" data-audio-us-female="/audios/us/individual-us-female.mp3"></span> - <span class="pho">u</span> also becomes <span class="pho">ə</span>, and there's a added <span class="pho">ʷ</span> sound between <span class="pho">u</span> and <span class="pho">ə</span>… In fact, many dictionaries now straightforwardly use the latter phonetic annotation.
-
-## 拼写（Spellings）
-
-### <span class="pho">ə</span>
-
-* **a**
-  * about <span class="pho alt">əˈbaʊt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/about-us-male.mp3" data-audio-us-female="/audios/us/about-us-female.mp3"></span>
-  * banana <span class="pho alt">bəˈnæn.ə</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/banana-us-male.mp3" data-audio-us-female="/audios/us/banana-us-female.mp3"></span>
-  * sofa <span class="pho alt">ˈsoʊ.fə</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sofa-us-male.mp3" data-audio-us-female="/audios/us/sofa-us-female.mp3"></span>
-* **e**
-  * open <span class="pho alt">ˈoʊ.pən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/open-us-male.mp3" data-audio-us-female="/audios/us/open-us-female.mp3"></span>
-  * problem <span class="pho alt">ˈprɑː.bləm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/problem-us-male.mp3" data-audio-us-female="/audios/us/problem-us-female.mp3"></span>
-  * synthesis <span class="pho alt">ˈsɪn.θə.sɪs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/synthesis-us-male.mp3" data-audio-us-female="/audios/us/synthesis-us-female.mp3"></span>
-* **i**
-  * animal <span class="pho alt">ˈæn.ɪ.məl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/animal-us-male.mp3" data-audio-us-female="/audios/us/animal-us-female.mp3"></span>
-  * president <span class="pho alt">ˈprez.ɪ.dənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/president-us-male.mp3" data-audio-us-female="/audios/us/president-us-female.mp3"></span>
-  * pupil <span class="pho alt">ˈpjuː.pəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pupil-us-male.mp3" data-audio-us-female="/audios/us/pupil-us-female.mp3"></span>
-* **o**
-  * bacon <span class="pho alt">ˈbeɪ.kən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bacon-us-male.mp3" data-audio-us-female="/audios/us/bacon-us-female.mp3"></span>
-  * lesson <span class="pho alt">ˈles.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/lesson-us-male.mp3" data-audio-us-female="/audios/us/lesson-us-female.mp3"></span>
-  * pilot <span class="pho alt">ˈpaɪ.lət</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pilot-us-male.mp3" data-audio-us-female="/audios/us/pilot-us-female.mp3"></span>
-* **u**
-  * circus <span class="pho alt">ˈsɝː.kəs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/circus-us-male.mp3" data-audio-us-female="/audios/us/circus-us-female.mp3"></span>
-  * medium <span class="pho alt">ˈmiː.di.əm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/medium-us-male.mp3" data-audio-us-female="/audios/us/medium-us-female.mp3"></span>
-  * support <span class="pho alt">səˈpɔːrt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/support-us-male.mp3" data-audio-us-female="/audios/us/support-us-female.mp3"></span>
-* **ou**
-  * courageous <span class="pho alt">kəˈreɪ.dʒəs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/courageous-us-male.mp3" data-audio-us-female="/audios/us/courageous-us-female.mp3"></span>
-  * famous <span class="pho alt">ˈfeɪ.məs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/famous-us-male.mp3" data-audio-us-female="/audios/us/famous-us-female.mp3"></span>
-  * humorous <span class="pho alt">ˈhjuː.mə.rəs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/humorous-us-male.mp3" data-audio-us-female="/audios/us/humorous-us-female.mp3"></span>
-
-### <span class="pho">ɚ</span>
-
-* **er**
-  * better <span class="pho alt">ˈbet̬.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/better-us-male.mp3" data-audio-us-female="/audios/us/better-us-female.mp3"></span>
-  * butter <span class="pho alt">ˈbʌt̬.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/butter-us-male.mp3" data-audio-us-female="/audios/us/butter-us-female.mp3"></span>
-  * teacher <span class="pho alt">ˈtiː.tʃɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/teacher-us-male.mp3" data-audio-us-female="/audios/us/teacher-us-female.mp3"></span>
-* **or**
-  * actor <span class="pho alt">ˈæk.tɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/actor-us-male.mp3" data-audio-us-female="/audios/us/actor-us-female.mp3"></span>
-  * doctor <span class="pho alt">ˈdɑːk.tɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/doctor-us-male.mp3" data-audio-us-female="/audios/us/doctor-us-female.mp3"></span>
-  * editor <span class="pho alt">ˈed.ɪ.t̬ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/editor-us-male.mp3" data-audio-us-female="/audios/us/editor-us-female.mp3"></span>
-* **ar**
-  * beggar <span class="pho alt">ˈbeɡ.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/beggar-us-male.mp3" data-audio-us-female="/audios/us/beggar-us-female.mp3"></span>
-  * burglar <span class="pho alt">ˈbɝː.ɡlɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/burglar-us-male.mp3" data-audio-us-female="/audios/us/burglar-us-female.mp3"></span>
-  * collar <span class="pho alt">ˈkɑː.lɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/collar-us-male.mp3" data-audio-us-female="/audios/us/collar-us-female.mp3"></span>
-* **ure**
-  * culture <span class="pho alt">ˈkʌl.tʃɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/culture-us-male.mp3" data-audio-us-female="/audios/us/culture-us-female.mp3"></span>
-  * figure <span class="pho alt">ˈfɪɡ.jɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/figure-us-male.mp3" data-audio-us-female="/audios/us/figure-us-female.mp3"></span>
-  * pressure <span class="pho alt">ˈpreʃ.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pressure-us-male.mp3" data-audio-us-female="/audios/us/pressure-us-female.mp3"></span>
-
-### <span class="pho">ɝː</span>
-
-* **er**
-  * her <span class="pho alt">hɝː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/her-us-male.mp3" data-audio-us-female="/audios/us/her-us-female.mp3"></span>
-  * term <span class="pho alt">tɝːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/term-us-male.mp3" data-audio-us-female="/audios/us/term-us-female.mp3"></span>
-  * clerk <span class="pho alt">klɝːk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/clerk-us-male.mp3" data-audio-us-female="/audios/us/clerk-us-female.mp3"></span>
-* **ear**
-  * earn <span class="pho alt">ɝːn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/earn-us-male.mp3" data-audio-us-female="/audios/us/earn-us-female.mp3"></span>
-  * earth <span class="pho alt">ɝːθ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/earth-us-male.mp3" data-audio-us-female="/audios/us/earth-us-female.mp3"></span>
-  * heard <span class="pho alt">hɝːd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/heard-us-male.mp3" data-audio-us-female="/audios/us/heard-us-female.mp3"></span>
-* **ir**
-  * bird <span class="pho alt">bɝːd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bird-us-male.mp3" data-audio-us-female="/audios/us/bird-us-female.mp3"></span>
-  * first <span class="pho alt">ˈfɝːst</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/first-us-male.mp3" data-audio-us-female="/audios/us/first-us-female.mp3"></span>
-  * stir <span class="pho alt">stɝː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/stir-us-male.mp3" data-audio-us-female="/audios/us/stir-us-female.mp3"></span>
-* **ur**
-  * burn <span class="pho alt">bɝːn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/burn-us-male.mp3" data-audio-us-female="/audios/us/burn-us-female.mp3"></span>
-  * nurse <span class="pho alt">nɝːs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/nurse-us-male.mp3" data-audio-us-female="/audios/us/nurse-us-female.mp3"></span>
-  * turn <span class="pho alt">tɝːn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/turn-us-male.mp3" data-audio-us-female="/audios/us/turn-us-female.mp3"></span>
-* **or**
-  * word <span class="pho alt">wɝːd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/word-us-male.mp3" data-audio-us-female="/audios/us/word-us-female.mp3"></span>
-  * world <span class="pho alt">wɝːld</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/world-us-male.mp3" data-audio-us-female="/audios/us/world-us-female.mp3"></span>
-  * worse <span class="pho alt">wɝːs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/worse-us-male.mp3" data-audio-us-female="/audios/us/worse-us-female.mp3"></span>
-
-[^1]: This illustration comes from https://globalspeechtherapy.com/how-to-teach-the-r-sound/
diff --git a/1000-hours/sounds-of-american-english-old/2.1.6-i.md b/1000-hours/sounds-of-american-english-old/2.1.6-i.md
deleted file mode 100644
index e4dc5e1f..00000000
--- a/1000-hours/sounds-of-american-english-old/2.1.6-i.md
+++ /dev/null
@@ -1,57 +0,0 @@
-# 2.1.6. <span class="pho">ɪ</span>/<span class="pho">i</span>/<span class="pho">iː</span>
-
-<span class="pho">ɪ</span> 并不是长元音 <span class="pho">iː</span> 的更短版本，它更像是 <span class="pho">e</span> 和 <span class="pho">i</span> 之间的一个音。听起来很像是更短版本的 <span class="pho">eɪ</span>，从唇形上来看<span class="pho">ɪ</span> 更接近 <span class="pho">e</span> 。
-
-The <span class="pho">ɪ</span> sound doesn't merely represent a shorter version of the long vowel <span class="pho">iː</span>. Instead, it seems to inhabit a space somewhere between <span class="pho">e</span> and <span class="pho">i</span>. It sounds more like a shorter rendition of <span class="pho">eɪ</span>, and visually speaking, the lip shape for <span class="pho">ɪ</span> is more akin to <span class="pho">e</span>.
-
-![vowels-mouth-shape-ɪ-i](/images/vowels-mouth-shape-ɪ-i.svg)
-
-另外，这个音实际上还有第 3 个版本，<span class="pho">ɪ</span> 在词汇末尾的时候，更倾向于像是 <span class="pho">iː</span> 这个长元音的更短版本，<span class="pho">i</span>，长度介于 <span class="pho">ɪ</span> 和 <span class="pho">iː</span> 之间 —— 也就是说，<span class="pho">i</span> 是个半长元音。比如，*responsibility* <span class="pho alt">rɪˌspɑːn·səˈbɪl·ə·t̬i</span><span class="speak-word-inline" data-audio-us-male="/audios/us/responsibility-us-male.mp3" data-audio-us-female="/audios/us/responsibility-us-female.mp3"></span>.
-
-In addition, this sound actually has a third variation. When <span class="pho">ɪ</span> appears at the end of words, it tends to sound more like a shortened version of the long vowel <span class="pho">iː</span> — <span class="pho">i</span>, with a length somewhere in between <span class="pho">ɪ</span> and <span class="pho">iː</span>, which means <span class="pho">i</span> is a *semi-long vowel*. For instance, in the word *responsibility <span class="pho alt">rɪˌspɑːn·səˈbɪl·ə·t̬i</span><span class="speak-word-inline" data-audio-us-male="/audios/us/responsibility-us-male.mp3" data-audio-us-female="/audios/us/responsibility-us-female.mp3"></span>.
-
-## 拼写（Spellings）
-
-### <span class="pho">ɪ</span>
-
-* **i**
-  * bit <span class="pho alt">bɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bit-us-male.mp3" data-audio-us-female="/audios/us/bit-us-female.mp3"></span>
-  * sit <span class="pho alt">sɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sit-us-male.mp3" data-audio-us-female="/audios/us/sit-us-female.mp3"></span>
-  * hill <span class="pho alt">hɪl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/hill-us-male.mp3" data-audio-us-female="/audios/us/hill-us-female.mp3"></span>
-* **y**
-  * gym <span class="pho alt">dʒɪm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/gym-us-male.mp3" data-audio-us-female="/audios/us/gym-us-female.mp3"></span>
-  * myth <span class="pho alt">mɪθ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/myth-us-male.mp3" data-audio-us-female="/audios/us/myth-us-female.mp3"></span>
-  * symbol <span class="pho alt">ˈsɪm.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/symbol-us-male.mp3" data-audio-us-female="/audios/us/symbol-us-female.mp3"></span>
-* **e**
-  * pretty <span class="pho alt">ˈprɪt̬.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pretty-us-male.mp3" data-audio-us-female="/audios/us/pretty-us-female.mp3"></span>
-  * English <span class="pho alt">ˈɪŋ.ɡlɪʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/English-us-male.mp3" data-audio-us-female="/audios/us/English-us-female.mp3"></span>
-* **ui**
-  * build <span class="pho alt">bɪld</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/build-us-male.mp3" data-audio-us-female="/audios/us/build-us-female.mp3"></span>
-  * guitar <span class="pho alt">ɡɪˈtɑːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/guitar-us-male.mp3" data-audio-us-female="/audios/us/guitar-us-female.mp3"></span>
-  * guilty <span class="pho alt">ˈɡɪl.ti</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/guilty-us-male.mp3" data-audio-us-female="/audios/us/guilty-us-female.mp3"></span>
-
-### <span class="pho">iː</span>
-
-* **ee**
-  * bee <span class="pho alt">biː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bee-us-male.mp3" data-audio-us-female="/audios/us/bee-us-female.mp3"></span>
-  * see <span class="pho alt">siː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/see-us-male.mp3" data-audio-us-female="/audios/us/see-us-female.mp3"></span>
-  * tree <span class="pho alt">triː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/tree-us-male.mp3" data-audio-us-female="/audios/us/tree-us-female.mp3"></span>
-* **ea**
-  * eat <span class="pho alt">iːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/eat-us-male.mp3" data-audio-us-female="/audios/us/eat-us-female.mp3"></span>
-  * beach <span class="pho alt">biːtʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/beach-us-male.mp3" data-audio-us-female="/audios/us/beach-us-female.mp3"></span>
-  * leave <span class="pho alt">liːv</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/leave-us-male.mp3" data-audio-us-female="/audios/us/leave-us-female.mp3"></span>
-* **e**
-  * he <span class="pho alt">hiː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/he-us-male.mp3" data-audio-us-female="/audios/us/he-us-female.mp3"></span>
-  * me <span class="pho alt">miː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/me-us-male.mp3" data-audio-us-female="/audios/us/me-us-female.mp3"></span>
-  * she <span class="pho alt">ʃiː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/she-us-male.mp3" data-audio-us-female="/audios/us/she-us-female.mp3"></span>
-* **ie**
-  * believe <span class="pho alt">bɪˈliːv</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/believe-us-male.mp3" data-audio-us-female="/audios/us/believe-us-female.mp3"></span>
-  * field <span class="pho alt">fiːld</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/field-us-male.mp3" data-audio-us-female="/audios/us/field-us-female.mp3"></span>
-  * chief <span class="pho alt">tʃiːf</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/chief-us-male.mp3" data-audio-us-female="/audios/us/chief-us-female.mp3"></span>
-
-### <span class="pho">i</span>
-
-* **y**
-  * happy <span class="pho alt">ˈhæp.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/happy-us-male.mp3" data-audio-us-female="/audios/us/happy-us-female.mp3"></span>
-  * certainly <span class="pho alt">ˈsɝː.tən.li</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/certainly-us-male.mp3" data-audio-us-female="/audios/us/certainly-us-female.mp3"></span>
-  * unexpectedly <span class="pho alt">ˌʌn.ɪkˈspek.tɪd.li</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/unexpectedly-us-male.mp3" data-audio-us-female="/audios/us/unexpectedly-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.1.7-u.md b/1000-hours/sounds-of-american-english-old/2.1.7-u.md
deleted file mode 100644
index e62b536f..00000000
--- a/1000-hours/sounds-of-american-english-old/2.1.7-u.md
+++ /dev/null
@@ -1,47 +0,0 @@
-# 2.1.7. <span class="pho">ʊ/u/uː</span>
-
-<span class="pho">u</span> 这个元音，地球上的任何语言都用，并且还几乎是一模一样地用，所以，大家读起来都不费劲。有一个细节值得注意，英文里长元音 <span class="pho">uː</span> 发声相对于短元音 <span class="pho">ʊ</span> 嘴唇相对更加略微凸出。请试着比较一下 *boot* <span class="pho alt">buːt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/boot-us-male.mp3" data-audio-us-female="/audios/us/boot-us-female.mp3"></span>和 *book* <span class="pho alt">bʊk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/book-us-male.mp3" data-audio-us-female="/audios/us/book-us-female.mp3"></span>.
-
-This pair of vowels is used in virtually every language on Earth, and it's used in almost exactly the same way, making it easy for everyone to pronounce. There's one detail worth noting: in English, the long vowel <span class="pho">uː</span> requires a smaller mouth shape than the short vowel <span class="pho">ʊ</span>, and lips should protrude slightly more. Try to compare *boot* <span class="pho alt">buːt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/boot-us-male.mp3" data-audio-us-female="/audios/us/boot-us-female.mp3"></span>and *book* <span class="pho alt">bʊk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/book-us-male.mp3" data-audio-us-female="/audios/us/book-us-female.mp3"></span>.
-
-另外，在 CEPD 中，这个音在非重音音节时被标注为 <span class="pho">u</span>，之前见到过的例子是 *situation* <span class="pho alt">ˌsɪtʃ·uˈeɪ·ʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/situation-us-male.mp3" data-audio-us-female="/audios/us/situation-us-female.mp3"></span>。
-
-Additionally, in the Cambridge English Pronouncing Dictionary (CEPD), when the sound occurs in an unstressed syllable, it is marked as <span class="pho">u</span>. For example, in the word situation, it's shown as <span class="pho alt">ˌsɪtʃ·uˈeɪ·ʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/situation-us-male.mp3" data-audio-us-female="/audios/us/situation-us-female.mp3"></span>.
-
-## 拼写（Spellings）
-
-### <span class="pho">ʊ</span>
-
-* **u**
-  * bush <span class="pho alt">bʊʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bush-us-male.mp3" data-audio-us-female="/audios/us/bush-us-female.mp3"></span>
-  * push <span class="pho alt">pʊʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/push-us-male.mp3" data-audio-us-female="/audios/us/push-us-female.mp3"></span>
-  * put <span class="pho alt">pʊt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/put-us-male.mp3" data-audio-us-female="/audios/us/put-us-female.mp3"></span>
-* **oo**
-  * book <span class="pho alt">bʊk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/book-us-male.mp3" data-audio-us-female="/audios/us/book-us-female.mp3"></span>
-  * good <span class="pho alt">ɡʊd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/good-us-male.mp3" data-audio-us-female="/audios/us/good-us-female.mp3"></span>
-  * wood <span class="pho alt">wʊd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/wood-us-male.mp3" data-audio-us-female="/audios/us/wood-us-female.mp3"></span>
-
-* **ou**
-  * could <span class="pho alt">kʊd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/could-us-male.mp3" data-audio-us-female="/audios/us/could-us-female.mp3"></span>
-  * should <span class="pho alt">ʃʊd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/should-us-male.mp3" data-audio-us-female="/audios/us/should-us-female.mp3"></span>
-  * would <span class="pho alt">wʊd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/would-us-male.mp3" data-audio-us-female="/audios/us/would-us-female.mp3"></span>
-
-### <span class="pho">uː</span>
-
-* **ew**
-  * chew <span class="pho alt">tʃuː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/chew-us-male.mp3" data-audio-us-female="/audios/us/chew-us-female.mp3"></span>
-  * drew <span class="pho alt">druː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/drew-us-male.mp3" data-audio-us-female="/audios/us/drew-us-female.mp3"></span>
-* **o**
-  * do <span class="pho alt">duː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/do-us-male.mp3" data-audio-us-female="/audios/us/do-us-female.mp3"></span>
-  * to <span class="pho alt">tuː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/to-us-male.mp3" data-audio-us-female="/audios/us/to-us-female.mp3"></span>
-  * who <span class="pho alt">huː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/who-us-male.mp3" data-audio-us-female="/audios/us/who-us-female.mp3"></span>
-* **oo**
-  * boot <span class="pho alt">buːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/boot-us-male.mp3" data-audio-us-female="/audios/us/boot-us-female.mp3"></span>
-  * food <span class="pho alt">fuːd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/food-us-male.mp3" data-audio-us-female="/audios/us/food-us-female.mp3"></span>
-  * moon <span class="pho alt">muːn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/moon-us-male.mp3" data-audio-us-female="/audios/us/moon-us-female.mp3"></span>
-* **u**
-  * June <span class="pho alt">dʒuːn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/June-us-male.mp3" data-audio-us-female="/audios/us/June-us-female.mp3"></span>
-  * rule <span class="pho alt">ruːl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/rule-us-male.mp3" data-audio-us-female="/audios/us/rule-us-female.mp3"></span>
-* **ue**
-  * glue <span class="pho alt">ɡluː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/glue-us-male.mp3" data-audio-us-female="/audios/us/glue-us-female.mp3"></span>
-  * true <span class="pho alt">truː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/true-us-male.mp3" data-audio-us-female="/audios/us/true-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.1.8-ɔ.md b/1000-hours/sounds-of-american-english-old/2.1.8-ɔ.md
deleted file mode 100644
index 37a31576..00000000
--- a/1000-hours/sounds-of-american-english-old/2.1.8-ɔ.md
+++ /dev/null
@@ -1,91 +0,0 @@
-# 2.1.8. <span class="pho">ɑː/ɔː/ɔːr</span>
-
-这一对元音在发声的时候，嘴唇动作非常明显，要在嘴唇形成一个小的圆形之后才开始发音。
-
-When pronouncing this pair of vowels, the lip movement is very noticeable. It's important to form a small circle with lips before beginning to vocalize.
-
-![vowels-mouth-shape-ɒ-ɔ](/images/vowels-mouth-shape-ɒ-ɔ.svg)
-
-在 CEPD 里，美音 <span class="pho">ɑː</span> 实际上对应的是英音里的短元音 <span class="pho">ɒ</span>。在美音里，<span class="pho">ɑː</span> 可以被理解为是个半长元音。
-
-In the Cambridge English Pronouncing Dictionary (CEPD), the American English vowel sound <span class="pho">ɑː</span> actually corresponds with the short vowel sound <span class="pho">ɒ</span> in British English. In American English, <span class="pho">ɑː</span> can be thought of as a *semi-long* vowel.
-
-与英音的 <span class="pho">ɒ</span> 相比，美音的 <span class="pho">ɑː</span> 会嘴巴张得更大一点，读得更长一点，听起来更像 <span class="pho">ɑ</span>，但口型略圆。比如，*dog*, 英音是 <span class="pho alt">dɒg</span><span class="speak-word-inline" data-audio-uk-male="/audios/us/dog-uk-male.mp3" data-audio-uk-female="/audios/us/dog-uk-female.mp3"></span>, 美音却是 <span class="pho alt">dɑːg</span><span class="speak-word-inline" data-audio-us-male="/audios/us/dog-us-male.mp3" data-audio-us-female="/audios/us/dog-us-female.mp3"></span>；而 *God*, 英音是 <span class="pho alt">gɒd</span><span class="speak-word-inline" data-audio-uk-male="/audios/us/god-uk-male.mp3" data-audio-uk-female="/audios/us/god-uk-female.mp3"></span>，美音同样相对更长一点，<span class="pho alt">gɑːd</span><span class="speak-word-inline" data-audio-us-male="/audios/us/god-us-male.mp3" data-audio-us-female="/audios/us/god-us-female.mp3"></span>。
-
-Compared to the British <span class="pho">ɒ</span>, the American <span class="pho">ɑː</span> is pronounced with a slightly more open mouth, held a bit longer, and sounds more like <span class="pho">ɑ</span>. However, the shape of the mouth is slightly rounded. For instance, for the word *dog*, in British English, it's pronounced as <span class="pho alt">dɒg</span><span class="speak-word-inline" data-audio-uk-male="/audios/us/dog-uk-male.mp3" data-audio-uk-female="/audios/us/dog-uk-female.mp3"></span>, while in American English, it's pronounced as <span class="pho alt">dɑːg</span><span class="speak-word-inline" data-audio-us-male="/audios/us/dog-us-male.mp3" data-audio-us-female="/audios/us/dog-us-female.mp3"></span>. Similarly, for *God*, it's <span class="pho alt">gɒd</span><span class="speak-word-inline" data-audio-uk-male="/audios/us/god-uk-male.mp3" data-audio-uk-female="/audios/us/god-uk-female.mp3"></span> in British English, but in American English it's elongated to <span class="pho alt">gɑːd</span><span class="speak-word-inline" data-audio-us-male="/audios/us/god-us-male.mp3" data-audio-us-female="/audios/us/god-us-female.mp3"></span>.
-
-但是，长元音 <span class="pho">ɔː</span> 在美式英语里，也许口型张得相对更大一些，但，并没有 <span class="pho">ɑ</span> 的音色。比如，*ordinary* <span class="pho alt">ˈɔːrdəneri</span><span class="speak-word-inline" data-audio-us-male="/audios/us/ordinary-us-male.mp3" data-audio-us-female="/audios/us/ordinary-us-female.mp3"></span> 或者 inventory <span class="pho alt">ˈɪnvəntɔːri</span><span class="speak-word-inline" data-audio-us-male="/audios/us/inventory-us-male.mp3" data-audio-us-female="/audios/us/inventory-us-female.mp3"></span>。
-
-However, the long vowel sound <span class="pho">ɔː</span> in American English might require a slightly wider mouth opening, but it doesn't have the flavor of <span class="pho">ɑ</span> sound. For example, *ordinary* <span class="pho alt">ˈɔːrdəneri</span><span class="speak-word-inline" data-audio-us-male="/audios/us/ordinary-us-male.mp3" data-audio-us-female="/audios/us/ordinary-us-female.mp3"></span> or *inventory* <span class="pho alt">ˈɪnvəntɔːri</span><span class="speak-word-inline" data-audio-us-male="/audios/us/inventory-us-male.mp3" data-audio-us-female="/audios/us/inventory-us-female.mp3"></span>.
-
-另外，在重读音节里，<span class="pho">ɔː</span> 可能会被美国人儿化，读成 <span class="pho">ɔːr</span> ，更像是双元音 <span class="pho">ɔər</span>。比如，*more* <span class="pho alt">mɔːr</span><span class="speak-word-inline" data-audio-us-male="/audios/us/more-us-male.mp3" data-audio-us-female="/audios/us/more-us-female.mp3"></span>。
-
-Additionally, in *stressed* syllables, <span class="pho">ɔː</span> might be rhotacized by Americans to sound like <span class="pho">ɔːr</span>, resembling the diphthong <span class="pho">ɔər</span>, for example, *more* <span class="pho alt">mɔːr</span><span class="speak-word-inline" data-audio-us-male="/audios/us/more-us-male.mp3" data-audio-us-female="/audios/us/more-us-female.mp3"></span>.
-
-## 拼写（Spellings）
-
-### <span class="pho">ɑː</span> (equivalent to British <span class="pho">ɒ</span>)
-
-* **a**
-  * father <span class="pho alt">ˈfɑː.ðɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/father-us-male.mp3" data-audio-us-female="/audios/us/father-us-female.mp3"></span>
-  * watch <span class="pho alt">wɑːtʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/watch-us-male.mp3" data-audio-us-female="/audios/us/watch-us-female.mp3"></span>
-  * wasp <span class="pho alt">wɑːsp</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/wasp-us-male.mp3" data-audio-us-female="/audios/us/wasp-us-female.mp3"></span>
-* **al**
-  * almond <span class="pho alt">ˈɑːl.mənd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/almond-us-male.mp3" data-audio-us-female="/audios/us/almond-us-female.mp3"></span>
-  * balm <span class="pho alt">bɑːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/balm-us-male.mp3" data-audio-us-female="/audios/us/balm-us-female.mp3"></span>
-  * palm <span class="pho alt">pɑːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/palm-us-male.mp3" data-audio-us-female="/audios/us/palm-us-female.mp3"></span>
-* **au**
-  * because <span class="pho alt">bɪˈkɑːz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/because-us-male.mp3" data-audio-us-female="/audios/us/because-us-female.mp3"></span>
-  * clause <span class="pho alt">klɑːz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/clause-us-male.mp3" data-audio-us-female="/audios/us/clause-us-female.mp3"></span>
-  * paunch <span class="pho alt">pɑːntʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/paunch-us-male.mp3" data-audio-us-female="/audios/us/paunch-us-female.mp3"></span>
-* **aw**
-  * drawn <span class="pho alt">drɑːn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/drawn-us-male.mp3" data-audio-us-female="/audios/us/drawn-us-female.mp3"></span>
-  * awning <span class="pho alt">ˈɑː.nɪŋ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/awning-us-male.mp3" data-audio-us-female="/audios/us/awning-us-female.mp3"></span>
-  * law <span class="pho alt">lɑː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/law-us-male.mp3" data-audio-us-female="/audios/us/law-us-female.mp3"></span>
-* **o**
-  * hot <span class="pho alt">hɑːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/hot-us-male.mp3" data-audio-us-female="/audios/us/hot-us-female.mp3"></span>
-  * dog <span class="pho alt">dɑːɡ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/dog-us-male.mp3" data-audio-us-female="/audios/us/dog-us-female.mp3"></span>
-  * log <span class="pho alt">lɑːɡ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/log-us-male.mp3" data-audio-us-female="/audios/us/log-us-female.mp3"></span>
-* **ough**
-  * bought <span class="pho alt">bɑːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bought-us-male.mp3" data-audio-us-female="/audios/us/bought-us-female.mp3"></span>
-  * thought <span class="pho alt">θɑːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/thought-us-male.mp3" data-audio-us-female="/audios/us/thought-us-female.mp3"></span>
-  * fought <span class="pho alt">fɑːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/fought-us-male.mp3" data-audio-us-female="/audios/us/fought-us-female.mp3"></span>
-
-### <span class="pho">ɔː</span>
-
-* **al**
-  * palsy <span class="pho alt">ˈpɔːl.zi</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/palsy-us-male.mp3" data-audio-us-female="/audios/us/palsy-us-female.mp3"></span>
-  * saltine <span class="pho alt">sɔːlˈtiːn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/saltine-us-male.mp3" data-audio-us-female="/audios/us/saltine-us-female.mp3"></span>
-  * wall <span class="pho alt">wɑːl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/wall-us-male.mp3" data-audio-us-female="/audios/us/wall-us-female.mp3"></span>
-* **au**
-  * aurora <span class="pho alt">ɔːˈrɔːr.ə</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/aurora-us-male.mp3" data-audio-us-female="/audios/us/aurora-us-female.mp3"></span>
-  * caudal <span class="pho alt">ˈkɔː.dəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/caudal-us-male.mp3" data-audio-us-female="/audios/us/caudal-us-female.mp3"></span>
-  * saute <span class="pho alt">sɔːˈteɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/saute-us-male.mp3" data-audio-us-female="/audios/us/saute-us-female.mp3"></span>
-* **aw**
-  * draw <span class="pho alt">drɔː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/draw-us-male.mp3" data-audio-us-female="/audios/us/draw-us-female.mp3"></span>
-  * saw <span class="pho alt">sɔː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/saw-us-male.mp3" data-audio-us-female="/audios/us/saw-us-female.mp3"></span>
-* **o**
-  * boring <span class="pho alt">ˈbɔː.rɪŋ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/boring-us-male.mp3" data-audio-us-female="/audios/us/boring-us-female.mp3"></span>
-  * orange <span class="pho alt">ˈɔːr.ɪndʒ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/orange-us-male.mp3" data-audio-us-female="/audios/us/orange-us-female.mp3"></span>
-  * inventory <span class="pho alt">ˈɪn.vən.tɔːr.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/inventory-us-male.mp3" data-audio-us-female="/audios/us/inventory-us-female.mp3"></span>
-
-### <span class="pho">ɔːr</span>
-
-* **or**
-  * fork <span class="pho alt">fɔːrk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/fork-us-male.mp3" data-audio-us-female="/audios/us/fork-us-female.mp3"></span>
-  * horse <span class="pho alt">hɔːrs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/horse-us-male.mp3" data-audio-us-female="/audios/us/horse-us-female.mp3"></span>
-  * short <span class="pho alt">ʃɔːrt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/short-us-male.mp3" data-audio-us-female="/audios/us/short-us-female.mp3"></span>
-* **oar**
-  * board <span class="pho alt">bɔːrd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/board-us-male.mp3" data-audio-us-female="/audios/us/board-us-female.mp3"></span>
-  * soar <span class="pho alt">sɔːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/soar-us-male.mp3" data-audio-us-female="/audios/us/soar-us-female.mp3"></span>
-  * roar <span class="pho alt">rɔːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/roar-us-male.mp3" data-audio-us-female="/audios/us/roar-us-female.mp3"></span>
-* **our**
-  * four <span class="pho alt">fɔːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/four-us-male.mp3" data-audio-us-female="/audios/us/four-us-female.mp3"></span>
-  * pour <span class="pho alt">pɔːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pour-us-male.mp3" data-audio-us-female="/audios/us/pour-us-female.mp3"></span>
-* **ore**
-  * core <span class="pho alt">kɔːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/core-us-male.mp3" data-audio-us-female="/audios/us/core-us-female.mp3"></span>
-  * more <span class="pho alt">mɔːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/more-us-male.mp3" data-audio-us-female="/audios/us/more-us-female.mp3"></span>
-  * shore <span class="pho alt">ʃɔːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/shore-us-male.mp3" data-audio-us-female="/audios/us/shore-us-female.mp3"></span>
-* **oor**
-  * door <span class="pho alt">dɔːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/door-us-male.mp3" data-audio-us-female="/audios/us/door-us-female.mp3"></span>
-  * floor <span class="pho alt">flɔːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/floor-us-male.mp3" data-audio-us-female="/audios/us/floor-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.1.9-aɪ.md b/1000-hours/sounds-of-american-english-old/2.1.9-aɪ.md
deleted file mode 100644
index 6e7c65b9..00000000
--- a/1000-hours/sounds-of-american-english-old/2.1.9-aɪ.md
+++ /dev/null
@@ -1,176 +0,0 @@
-# 2.1.9. <span class="pho">aɪ, eɪ, ɔɪ, aʊ, oʊ, er, ɪr, ʊr</span>
-
-亚洲语系基本上都没有和英文一样**长度**的**双元音**。韩文日文的母音和中文的韵母虽然都有少数由两个基础音素构成的组合音，但，它们和英文的双元音不同的地方在于，它们都是和其它韵母或者母音**等长**的，而不是像英文双元音的长度那样几乎是短元音的**两倍**。
-
-Essentially, Asian languages don't have *diphthongs* that are as *long* as those in English. Though Korean, Japanese, and Chinese vowels include a few compound sounds made of two basic vowel phonemes, they differ from English diphthongs. In these languages, the compound sounds are the *same length* as other vowels, not almost *double the length* like English diphthongs.
-
-比如，当中国人说 “太累了”<span class="speak-word-inline" data-audio-other="/audios/us/太累了-zh-cn-male.mp3"></span> 的时候，“太”（<span class="pho">tài</span>）这个字的 “韵母” 就很接近英文的双元音 <span class="pho">aɪ</span>；“累”（<span class="pho">lèi</span>）这个字的韵母就很接近英文的双元音 <span class="pho">eɪ</span>…… 但，它们很不一样，英文的双元音就是相对更长。
-
-For instance, when Chinese say *too tired* or "太累了"<span class="speak-word-inline" data-audio-other="/audios/us/太累了-zh-cn-male.mp3"></span>, the syllable <span class="pho">tài</span> has a vowel sound that closely resembles the English diphthong <span class="pho">aɪ</span>, and the vowel in <span class="pho">lèi</span> mimics the English diphthong <span class="pho">eɪ</span>. Despite these similarities, they're not identical - English diphthongs tend to be *longer* in duration.
-
-英文的双元音，都是两个元音的组合。它们都是从第一个元音**滑**向第二个元音，所以，它们从长度上来看，相当于是长元音；**节奏**在感觉上大抵是乐谱里的 “一拍里均放着三个等长音符的三连音”，前一个音素更长一些，后一个音素相对较短。
-
-In English, diphthongs are a combination of two vowel sounds. They *glide* from the first vowel to the second, making them similar in length to long vowels. In terms of *rhythm*, you can think of them like a triplet in music, where three notes of equal length fit within one beat. The first sound tends to be slightly longer, while the second sound is a bit shorter.
-
-读 <span class="pho">aɪ, eɪ, ɔɪ</span> 的时候，唇形分别从 <span class="pho">ɑ, e, ɔ</span> 开始，唇形保持不变，用喉咙完成从起始元音到 <span class="pho">ɪ</span> 的过度。
-
-When pronouncing the sounds <span class="pho">aɪ, eɪ, ɔɪ</span>, begin with the mouth shapes for <span class="pho">ɑ, e, ɔ</span> respectively. Keep lips in the same position and use throat to glide from the initial vowel sound to <span class="pho">ɪ</span>.
-
-![vowels-mouth-shape-aɪ](/images/vowels-mouth-shape-aɪ.svg)
-
-读 <span class="pho">er, ɪr, ʊr</span> 的时候，也一样，唇形分别从 <span class="pho">e, ɪ, ʊ</span> 开始，唇形保持不变，用喉咙完成从起始元音到 <span class="pho">ɚ</span> 的过度。美音会儿化这个 <span class="pho">ə</span>，所以是 <span class="pho">eɚ, ɪɚ, ʊɚ</span>，于是干脆写成 <span class="pho">er, ɪr, ʊr</span>。
-
-When pronouncing <span class="pho">er, ɪr, ʊr</span>, it's the same process. Start with the mouth shapes for <span class="pho">e, ɪ, ʊ</span>, keep lips steady, and use your throat to glide from the initial vowel to rhotacized <span class="pho">ɚ</span>, so it becomes <span class="pho">eɚ, ɪɚ, ʊɚ</span>, which are written as <span class="pho">er, ɪr, ʊr</span>.
-
-![vowels-mouth-shape-eə](/images/vowels-mouth-shape-eə.svg)
-
-读 <span class="pho">aʊ, oʊ</span> 的时候，唇形有变化，要分别从 <span class="pho">ɑ, ə</span> 开始，而后过度到 <span class="pho">ʊ</span>。
-
-![vowels-mouth-shape-aʊ](/images/vowels-mouth-shape-aʊ.svg)
-
-When pronouncing the sounds <span class="pho">aʊ, oʊ</span>, mouth shape should *change*. Start with the sounds <span class="pho">ɑ, ə</span> respectively, then glide towards the <span class="pho">ʊ</span> sound.
-
-在读它们的时候，重要的是，要把它们读得**足够长** —— 几乎要占用两个元音的发声时长，并且足够饱满。
-
-When pronouncing them, it's crucial to draw out the sounds - because they're taking the duration of two vowels - and make sure they are full and rich.
-
-## 拼写（Spellings）
-
-### <span class="pho">aɪ</span>
-
-* **i**
-  * align <span class="pho alt">əˈlaɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/align-us-male.mp3" data-audio-us-female="/audios/us/align-us-female.mp3"></span>
-  * ice <span class="pho alt">aɪs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/ice-us-male.mp3" data-audio-us-female="/audios/us/ice-us-female.mp3"></span>
-  * spider <span class="pho alt">ˈspaɪ.dɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/spider-us-male.mp3" data-audio-us-female="/audios/us/spider-us-female.mp3"></span>
-* **ie**
-  * lies <span class="pho alt">laɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/lies-us-male.mp3" data-audio-us-female="/audios/us/lies-us-female.mp3"></span>
-  * pie <span class="pho alt">paɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pie-us-male.mp3" data-audio-us-female="/audios/us/pie-us-female.mp3"></span>
-  * tie <span class="pho alt">taɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/tie-us-male.mp3" data-audio-us-female="/audios/us/tie-us-female.mp3"></span>
-* **igh**
-  * high <span class="pho alt">haɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/high-us-male.mp3" data-audio-us-female="/audios/us/high-us-female.mp3"></span>
-  * light <span class="pho alt">laɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/light-us-male.mp3" data-audio-us-female="/audios/us/light-us-female.mp3"></span>
-  * night <span class="pho alt">naɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/night-us-male.mp3" data-audio-us-female="/audios/us/night-us-female.mp3"></span>
-* **uy**
-  * buy <span class="pho alt">baɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/buy-us-male.mp3" data-audio-us-female="/audios/us/buy-us-female.mp3"></span>
-  * guy <span class="pho alt">ɡaɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/guy-us-male.mp3" data-audio-us-female="/audios/us/guy-us-female.mp3"></span>
-* **y**
-  * cry <span class="pho alt">kraɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/cry-us-male.mp3" data-audio-us-female="/audios/us/cry-us-female.mp3"></span>
-  * fly <span class="pho alt">flaɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/fly-us-male.mp3" data-audio-us-female="/audios/us/fly-us-female.mp3"></span>
-  * supply <span class="pho alt">səˈplaɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/supply-us-male.mp3" data-audio-us-female="/audios/us/supply-us-female.mp3"></span>
-
-### <span class="pho">eɪ</span>
-
-* **a**
-  * cake <span class="pho alt">keɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/cake-us-male.mp3" data-audio-us-female="/audios/us/cake-us-female.mp3"></span>
-  * make <span class="pho alt">meɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/make-us-male.mp3" data-audio-us-female="/audios/us/make-us-female.mp3"></span>
-  * table <span class="pho alt">ˈteɪ.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/table-us-male.mp3" data-audio-us-female="/audios/us/table-us-female.mp3"></span>
-* **ai**
-  * paint <span class="pho alt">peɪnt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/paint-us-male.mp3" data-audio-us-female="/audios/us/paint-us-female.mp3"></span>
-  * rain <span class="pho alt">reɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/rain-us-male.mp3" data-audio-us-female="/audios/us/rain-us-female.mp3"></span>
-  * train <span class="pho alt">reɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/train-us-male.mp3" data-audio-us-female="/audios/us/train-us-female.mp3"></span>
-* **ay**
-  * day <span class="pho alt">deɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/day-us-male.mp3" data-audio-us-female="/audios/us/day-us-female.mp3"></span>
-  * play <span class="pho alt">pleɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/play-us-male.mp3" data-audio-us-female="/audios/us/play-us-female.mp3"></span>
-  * stay <span class="pho alt">steɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/stay-us-male.mp3" data-audio-us-female="/audios/us/stay-us-female.mp3"></span>
-* **ea**
-  * break <span class="pho alt">breɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/break-us-male.mp3" data-audio-us-female="/audios/us/break-us-female.mp3"></span>
-  * great <span class="pho alt">ɡreɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/great-us-male.mp3" data-audio-us-female="/audios/us/great-us-female.mp3"></span>
-  * steak <span class="pho alt">steɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/steak-us-male.mp3" data-audio-us-female="/audios/us/steak-us-female.mp3"></span>
-* **ei**/**eigh**
-  * eight <span class="pho alt">eɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/eight-us-male.mp3" data-audio-us-female="/audios/us/eight-us-female.mp3"></span>
-  * reign <span class="pho alt">reɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/reign-us-male.mp3" data-audio-us-female="/audios/us/reign-us-female.mp3"></span>
-  * vein <span class="pho alt">veɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/vein-us-male.mp3" data-audio-us-female="/audios/us/vein-us-female.mp3"></span>
-  * weight <span class="pho alt">weɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/weight-us-male.mp3" data-audio-us-female="/audios/us/weight-us-female.mp3"></span>
-* **ey**
-  * grey <span class="pho alt">ɡreɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/grey-us-male.mp3" data-audio-us-female="/audios/us/grey-us-female.mp3"></span>
-  * survey <span class="pho alt">ˈsɝː.veɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/survey-us-male.mp3" data-audio-us-female="/audios/us/survey-us-female.mp3"></span>
-  * they <span class="pho alt">ðeɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/they-us-male.mp3" data-audio-us-female="/audios/us/they-us-female.mp3"></span>
-
-### <span class="pho">ɔɪ</span>
-
-* **oi**
-  * join <span class="pho alt">dʒɔɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/join-us-male.mp3" data-audio-us-female="/audios/us/join-us-female.mp3"></span>
-  * voice <span class="pho alt">vɔɪs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/voice-us-male.mp3" data-audio-us-female="/audios/us/voice-us-female.mp3"></span>
-* **oy**
-  * boy <span class="pho alt">bɔɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/boy-us-male.mp3" data-audio-us-female="/audios/us/boy-us-female.mp3"></span>
-  * joy <span class="pho alt">dʒɔɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/joy-us-male.mp3" data-audio-us-female="/audios/us/joy-us-female.mp3"></span>
-  * toy <span class="pho alt">tɔɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/toy-us-male.mp3" data-audio-us-female="/audios/us/toy-us-female.mp3"></span>
-
-### <span class="pho">aʊ</span>
-
-* **au**
-  * kraut <span class="pho alt">kraʊt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/kraut-us-male.mp3" data-audio-us-female="/audios/us/kraut-us-female.mp3"></span>
-* **ou**
-  * house <span class="pho alt">haʊs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/house-us-male.mp3" data-audio-us-female="/audios/us/house-us-female.mp3"></span>
-  * out <span class="pho alt">aʊt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/out-us-male.mp3" data-audio-us-female="/audios/us/out-us-female.mp3"></span>
-* **ow**
-  * brown <span class="pho alt">braʊn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/brown-us-male.mp3" data-audio-us-female="/audios/us/brown-us-female.mp3"></span>
-  * cow <span class="pho alt">kaʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/cow-us-male.mp3" data-audio-us-female="/audios/us/cow-us-female.mp3"></span>
-  * flower <span class="pho alt">ˈflaʊ.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/flower-us-male.mp3" data-audio-us-female="/audios/us/flower-us-female.mp3"></span>
-
-### <span class="pho">oʊ</span>
-
-* **o**
-  * go <span class="pho alt">ɡoʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/go-us-male.mp3" data-audio-us-female="/audios/us/go-us-female.mp3"></span>
-  * no <span class="pho alt">noʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/no-us-male.mp3" data-audio-us-female="/audios/us/no-us-female.mp3"></span>
-  * so <span class="pho alt">soʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/so-us-male.mp3" data-audio-us-female="/audios/us/so-us-female.mp3"></span>
-* **oa**
-  * boat <span class="pho alt">boʊt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/boat-us-male.mp3" data-audio-us-female="/audios/us/boat-us-female.mp3"></span>
-  * road <span class="pho alt">roʊd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/road-us-male.mp3" data-audio-us-female="/audios/us/road-us-female.mp3"></span>
-  * soap <span class="pho alt">soʊp</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/soap-us-male.mp3" data-audio-us-female="/audios/us/soap-us-female.mp3"></span>
-* **oe**
-  * Joe <span class="pho alt">dʒoʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/Joe-us-male.mp3" data-audio-us-female="/audios/us/Joe-us-female.mp3"></span>
-  * foe <span class="pho alt">foʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/foe-us-male.mp3" data-audio-us-female="/audios/us/foe-us-female.mp3"></span>
-  * toe <span class="pho alt">toʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/toe-us-male.mp3" data-audio-us-female="/audios/us/toe-us-female.mp3"></span>
-* **ow**
-  * blow <span class="pho alt">bloʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/blow-us-male.mp3" data-audio-us-female="/audios/us/blow-us-female.mp3"></span>
-  * grow <span class="pho alt">ɡroʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/grow-us-male.mp3" data-audio-us-female="/audios/us/grow-us-female.mp3"></span>
-  * show <span class="pho alt">ʃoʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/show-us-male.mp3" data-audio-us-female="/audios/us/show-us-female.mp3"></span>
-* **ough**
-  * though <span class="pho alt">ðoʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/though-us-male.mp3" data-audio-us-female="/audios/us/though-us-female.mp3"></span>
-  * dough <span class="pho alt">doʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/dough-us-male.mp3" data-audio-us-female="/audios/us/dough-us-female.mp3"></span>
-* **ew**
-  * sew <span class="pho alt">soʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sew-us-male.mp3" data-audio-us-female="/audios/us/sew-us-female.mp3"></span>
-
-### <span class="pho">er</span>
-
-* **ear**
-  * bear <span class="pho alt">ber</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bear-us-male.mp3" data-audio-us-female="/audios/us/bear-us-female.mp3"></span>
-* **air**
-  * air <span class="pho alt">er</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/air-us-male.mp3" data-audio-us-female="/audios/us/air-us-female.mp3"></span>
-  * fair <span class="pho alt">er</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/fair-us-male.mp3" data-audio-us-female="/audios/us/fair-us-female.mp3"></span>
-  * pair <span class="pho alt">er</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pair-us-male.mp3" data-audio-us-female="/audios/us/pair-us-female.mp3"></span>
-* **are**
-  * care <span class="pho alt">ker</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/care-us-male.mp3" data-audio-us-female="/audios/us/care-us-female.mp3"></span>
-  * fare <span class="pho alt">fer</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/fare-us-male.mp3" data-audio-us-female="/audios/us/fare-us-female.mp3"></span>
-  * ware <span class="pho alt">wer</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/ware-us-male.mp3" data-audio-us-female="/audios/us/ware-us-female.mp3"></span>
-
-### <span class="pho">ɪr</span>
-
-* **eer**
-  * cheer <span class="pho alt">tʃɪr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/cheer-us-male.mp3" data-audio-us-female="/audios/us/cheer-us-female.mp3"></span>
-  * deer <span class="pho alt">dɪr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/deer-us-male.mp3" data-audio-us-female="/audios/us/deer-us-female.mp3"></span>
-  * steer <span class="pho alt">stɪr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/steer-us-male.mp3" data-audio-us-female="/audios/us/steer-us-female.mp3"></span>
-* **ear**
-  * clear <span class="pho alt">klɪr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/clear-us-male.mp3" data-audio-us-female="/audios/us/clear-us-female.mp3"></span>
-  * fear <span class="pho alt">fɪr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/fear-us-male.mp3" data-audio-us-female="/audios/us/fear-us-female.mp3"></span>
-  * near <span class="pho alt">nɪr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/near-us-male.mp3" data-audio-us-female="/audios/us/near-us-female.mp3"></span>
-* **ier**
-  * fierce <span class="pho alt">fɪrs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/fierce-us-male.mp3" data-audio-us-female="/audios/us/fierce-us-female.mp3"></span>
-  * pier <span class="pho alt">pɪr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pier-us-male.mp3" data-audio-us-female="/audios/us/pier-us-female.mp3"></span>
-* **eir**
-  * weird <span class="pho alt">wɪrd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/weird-us-male.mp3" data-audio-us-female="/audios/us/weird-us-female.mp3"></span>
-
-### <span class="pho">ʊr</span>
-
-* **ure**
-  * cure <span class="pho alt">kjʊr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/cure-us-male.mp3" data-audio-us-female="/audios/us/cure-us-female.mp3"></span>
-  * pure <span class="pho alt">pjʊr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pure-us-male.mp3" data-audio-us-female="/audios/us/pure-us-female.mp3"></span>
-  * sure <span class="pho alt">ʃʊr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sure-us-male.mp3" data-audio-us-female="/audios/us/sure-us-female.mp3"></span>
-* **our**
-  * tour <span class="pho alt">tʊr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/tour-us-male.mp3" data-audio-us-female="/audios/us/tour-us-female.mp3"></span>
-  * velour <span class="pho alt">vəˈlʊr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/velour-us-male.mp3" data-audio-us-female="/audios/us/velour-us-female.mp3"></span>
-  * your <span class="pho alt">jʊr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/your-us-male.mp3" data-audio-us-female="/audios/us/your-us-female.mp3"></span>
-* **oor**
-  * poor <span class="pho alt">pʊr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/poor-us-male.mp3" data-audio-us-female="/audios/us/poor-us-female.mp3"></span>
-  * moor <span class="pho alt">mʊr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/moor-us-male.mp3" data-audio-us-female="/audios/us/moor-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.2-consonants.md b/1000-hours/sounds-of-american-english-old/2.2-consonants.md
deleted file mode 100644
index 83d257d4..00000000
--- a/1000-hours/sounds-of-american-english-old/2.2-consonants.md
+++ /dev/null
@@ -1,10 +0,0 @@
-# 2.2. 辅音（Consonants）
-
-地球上的所有语言都一样，在自然语流中，**辅音**不会单独存在。单独的**元音**，可以构成**音节**，也可以构成或者表达意义。比如，*ah* <span class="pho alt">ɑː</span>, *oh* <span class="pho alt">oʊ</span>，或者 *Uh-Oh* <span class="pho alt">ˈʌoʊ</span><span class="speak-word-inline" data-audio-us-female="/audios/us/Uh-Oh.mp3"></span>。但，绝大多数**辅音**必须依附于**元音**才能构成**音节**，并且，单独的辅音也不能构成意义。
-
-All languages on Earth follow a similar pattern: in the flow of natural speech, consonants *never* stand alone. Isolated vowels, however, can form syllables and convey meaning. For instance, you have sounds like *ah* <span class="pho alt">ɑː</span>, *oh* <span class="pho alt">oʊ</span>, or *O'Oh* <span class="pho alt">ˈɑoʊ</span>. But consonants almost always need to be attached to vowels to form *syllables*, and alone, they don't carry meaning.
-
-注意：有三个辅音，<span class="pho">l</span>, <span class="pho">m</span>, <span class="pho">n</span>，被称作 “音节辅音”，因为它们自带 <span class="pho">ə</span> 的音色。比如，*bottle* <span class="pho alt">ˈbɑːtl</span>, *bottom* <span class="pho alt">ˈbɑːtm</span>, button <span class="pho alt">ˈbʌtn</span>。有些词典会用 <span class="pho">ᵊ</span>，比如写成：
-*bottle* <span class="pho alt">ˈbɑːtᵊl</span>, *bottom* <span class="pho alt">ˈbɑːtᵊm</span>, button <span class="pho alt">ˈbʌtᵊn</span>。剑桥词典的标注方式是：*bottle* <span class="pho alt">ˈbɑːt̬əl</span>, *bottom* <span class="pho alt">ˈbɑːt̬əm</span>, *button* <span class="pho alt">ˈbʌtən</span>…… 
-
-Please note, in English, there are three consonants — <span class="pho">l</span>, <span class="pho">m</span>, and <span class="pho">n</span> — that can act as "syllabic consonants." This means they carry a vocalic quality similar to the schwa sound <span class="pho">ə</span>. For instance, in words like *bottle* <span class="pho alt">ˈbɑːtl</span>, *bottom* <span class="pho alt">ˈbɑːtm</span>, and *button* <span class="pho alt">ˈbʌtn</span>, you can hear this quality. Some dictionaries use the symbol <span class="pho">ᵊ</span> to indicate this sound, rendering the words as follows: *bottle* <span class="pho alt">ˈbɑːtᵊl</span>, *bottom* <span class="pho alt">ˈbɑːtᵊm</span>, *button* <span class="pho alt">ˈbʌtᵊn</span>. The Cambridge Dictionary, however, uses a slightly different notation: *bottle* <span class="pho alt">ˈbɑːt̬əl</span>, *bottom* <span class="pho alt">ˈbɑːt̬əm</span>, *button* <span class="pho alt">ˈbʌtən</span>.
diff --git a/1000-hours/sounds-of-american-english-old/2.2.1-categorization.md b/1000-hours/sounds-of-american-english-old/2.2.1-categorization.md
deleted file mode 100644
index 99a93466..00000000
--- a/1000-hours/sounds-of-american-english-old/2.2.1-categorization.md
+++ /dev/null
@@ -1,34 +0,0 @@
-# 2.2.1. 辅音分类（Categorization of Consonants）
-
-辅音可以根据发声时**声带**是否震动被分为清辅音（voiceless consonants）与浊辅音（voiced consonants）。清辅音只有气流震动，没有声带振动，而浊辅音的气流震动却伴有声带振动。比如，<span class="pho">s</span> 是清辅音，<span class="pho">z</span> 是浊辅音。
-
-Consonants can be classified into two categories based on whether or not the vocal cords vibrate when the sound is produced. These two categories are voiceless consonants and voiced consonants. Voiceless consonants are produced solely by the vibration of air flow, without the involvement of the vocal cords. Voiced consonants, on the other hand, are produced by the vibration of both the air flow and the vocal cords. For instance, <span class="pho">s</span> is a voiceless consonant, while <span class="pho">z</span> is a voiced consonant.
-
-|           | consonants                                                                   |
-| --------- | ---------------------------------------------------------------------------- |
-| voiceless | <span class="pho">p</span>, <span class="pho">t</span>, <span class="pho">k</span>, <span class="pho">f</span>, <span class="pho">s</span>, <span class="pho">θ</span>, <span class="pho">ʃ</span>, <span class="pho">h</span>, <span class="pho">tʃ</span>, <span class="pho">tr</span>, <span class="pho">ts</span>                     |
-| voiced    | <span class="pho">b</span>, <span class="pho">d</span>, <span class="pho">g</span>, <span class="pho">v</span>, <span class="pho">z</span>, <span class="pho">ð</span>, <span class="pho">ʒ</span>, <span class="pho">r</span>, <span class="pho">dʒ</span>, <span class="pho">dr</span>, <span class="pho">dz</span>, <span class="pho">m</span>, <span class="pho">n</span>, <span class="pho">ŋ</span>, <span class="pho">l</span> |
-
-<span class="pho">w</span> 和 <span class="pho">y</span> 这两个辅音被称为**半元音** —— 无法用声带振动与否分类。
-
-The consonants <span class="pho">w</span> and <span class="pho">y</span> are referred to as *semi-vowels* - they can't be categorized based on whether the vocal cords vibrate or not.
-
-辅音的另外一个划分，是根据**气流**振动的方式和位置。
-
-Another way to categorize consonants is based on the method and location of airflow vibration.
-
-| Airflow   | Voiced or not | Consonants              |
-| --------- | ------------- | ----------------------- |
-| Plosive   | Voiceless     | <span class="pho">p</span>, <span class="pho">t</span>, <span class="pho">k</span>           |
-|           | Voiced        | <span class="pho">b</span>, <span class="pho">d</span>, <span class="pho">g</span>           |
-| Fricative | Voiceless     | <span class="pho">f</span>, <span class="pho">s</span>, <span class="pho">θ</span>, <span class="pho">ʃ</span>, <span class="pho">h</span> |
-|           | Voiced        | <span class="pho">v</span>, <span class="pho">z</span>, <span class="pho">ð</span>, <span class="pho">ʒ</span>      |
-| Affricate | Voiceless     | <span class="pho">tʃ</span>, <span class="pho">tr</span>, <span class="pho">ts</span>        |
-|           | Voiced        | <span class="pho">dʒ</span>, <span class="pho">dr</span>, <span class="pho">dz</span>        |
-| Nasal     | Voiced        | <span class="pho">m</span>, <span class="pho">n</span>, <span class="pho">ŋ</span>           |
-| Lateral   | Voiced        | <span class="pho">l</span>, <span class="pho">r</span>                |
-| Semivowel |               | <span class="pho">j</span>, <span class="pho">w</span>                |
-
-作为初学者，**你无需尝试记忆这些分类和术语** —— 除非将来你有多余的时间精力。这些语言学的概念，并不构成任何学习障碍。你需要了解的只不过是分类的**依据**：**声带振动与否**，以及**气流振动方式和位置**。
-
-As a beginner, **there's no need for you to try and memorize these categories, and terms** — unless you find some extra time and energy in the future. These linguistic concepts won't pose any learning obstacles. What you need to understand are the *criteria* used for classifications: *whether the vocal cords vibrate or not*, as well as *the method and location of airflow vibration*.
\ No newline at end of file
diff --git a/1000-hours/sounds-of-american-english-old/2.2.10-tʃdʒ.md b/1000-hours/sounds-of-american-english-old/2.2.10-tʃdʒ.md
deleted file mode 100644
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--- a/1000-hours/sounds-of-american-english-old/2.2.10-tʃdʒ.md
+++ /dev/null
@@ -1,51 +0,0 @@
-# 2.2.10. <span class="pho">tʃ/dʒ</span>
-
-<span class="pho">ʃ/ʒ</span> 发声时舌尖贴近但没有接触到龈脊，<span class="pho">tʃ/dʒ</span> 则需要舌尖贴到龈脊，和 <span class="pho">t/d</span> 一样；但，无论是 <span class="pho">ʃ/ʒ</span> 还是 <span class="pho">tʃ/dʒ</span> 发声时舌背都抬得较高，舌尾抵到后牙。
-
-When pronouncing <span class="pho">ʃ/ʒ</span>, the tip of your tongue should be close to, but not touching, the alveolar ridge. For <span class="pho">tʃ/dʒ</span>, however, you need to touch the alveolar ridge with your tongue tip, same as when pronouncing <span class="pho">t/d</span>. However, when pronouncing either the sounds <span class="pho">ʃ/ʒ</span> or <span class="pho">tʃ/dʒ</span>, the tongue roof should arch higher in the mouth, with the back of it touching back teeth.
-
-![articulator-tongue-tip-td](/images/articulator-tongue-tip-chzh.svg)
-
-为了让舌尖适应那个部位，不妨反复练习：
-
-To get your tongue used to this position, it's a good idea to practice repeatedly:
-
-> * <span class="pho">ʃ... tʃ... ʃ... tʃ... ʃ... tʃ... ʃ... tʃ... ʃ... tʃ...</span>
-> * <span class="pho">ʒ... dʒ... ʒ... dʒ... ʒ... dʒ... ʒ... dʒ... ʒ... dʒ...</span>
-> * <span class="pho">ʃ... ʒ... ʃ... ʒ... ʃ... ʒ... ʃ... ʒ... ʃ... ʒ...</span>
-> * <span class="pho">tʃ... dʒ... tʃ... dʒ... tʃ... dʒ... tʃ... dʒ... tʃ... dʒ...</span>
-
-## 拼写（Spellings）
-
-### <span class="pho">ʧ</span>
-
-* **ch**
-  * charm <span class="pho alt">tʃɑːrm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/charm-us-male.mp3" data-audio-us-female="/audios/us/charm-us-female.mp3"></span>
-  * church <span class="pho alt">tʃɝːtʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/church-us-male.mp3" data-audio-us-female="/audios/us/church-us-female.mp3"></span>
-  * teach <span class="pho alt">tiːtʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/teach-us-male.mp3" data-audio-us-female="/audios/us/teach-us-female.mp3"></span>
-* **tch**
-  * match <span class="pho alt">mætʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/match-us-male.mp3" data-audio-us-female="/audios/us/match-us-female.mp3"></span>
-  * pitch <span class="pho alt">pɪtʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pitch-us-male.mp3" data-audio-us-female="/audios/us/pitch-us-female.mp3"></span>
-  * watch <span class="pho alt">wɑːtʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/watch-us-male.mp3" data-audio-us-female="/audios/us/watch-us-female.mp3"></span>
-* **t** (+ure)
-  * creature <span class="pho alt">ˈkriː.tʃɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/creature-us-male.mp3" data-audio-us-female="/audios/us/creature-us-female.mp3"></span>
-  * future <span class="pho alt">ˈfjuː.tʃɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/future-us-male.mp3" data-audio-us-female="/audios/us/future-us-female.mp3"></span>
-  * nature <span class="pho alt">ˈneɪ.tʃɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/nature-us-male.mp3" data-audio-us-female="/audios/us/nature-us-female.mp3"></span>
-
-### <span class="pho">dʒ</span>
-
-* **d**
-  * soldier <span class="pho alt">ˈsoʊl.dʒɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/soldier-us-male.mp3" data-audio-us-female="/audios/us/soldier-us-female.mp3"></span>
-  * procedure <span class="pho alt">prəˈsiː.dʒɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/procedure-us-male.mp3" data-audio-us-female="/audios/us/procedure-us-female.mp3"></span>
-* **g**
-  * gentle <span class="pho alt">ˈdʒen.t̬əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/gentle-us-male.mp3" data-audio-us-female="/audios/us/gentle-us-female.mp3"></span>
-  * giant <span class="pho alt">ˈdʒaɪ.ənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/giant-us-male.mp3" data-audio-us-female="/audios/us/giant-us-female.mp3"></span>
-  * rage <span class="pho alt">reɪdʒ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/rage-us-male.mp3" data-audio-us-female="/audios/us/rage-us-female.mp3"></span>
-* **dg**
-  * badge <span class="pho alt">bædʒ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/badge-us-male.mp3" data-audio-us-female="/audios/us/badge-us-female.mp3"></span>
-  * bridge <span class="pho alt">brɪdʒ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bridge-us-male.mp3" data-audio-us-female="/audios/us/bridge-us-female.mp3"></span>
-  * judge <span class="pho alt">dʒʌdʒ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/judge-us-male.mp3" data-audio-us-female="/audios/us/judge-us-female.mp3"></span>
-* **j**
-  * job <span class="pho alt">dʒɑːb</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/job-us-male.mp3" data-audio-us-female="/audios/us/job-us-female.mp3"></span>
-  * joy <span class="pho alt">dʒɔɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/joy-us-male.mp3" data-audio-us-female="/audios/us/joy-us-female.mp3"></span>
-  * jump <span class="pho alt">dʒʌmp</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/jump-us-male.mp3" data-audio-us-female="/audios/us/jump-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.2.11-trdr.md b/1000-hours/sounds-of-american-english-old/2.2.11-trdr.md
deleted file mode 100644
index 73ada864..00000000
--- a/1000-hours/sounds-of-american-english-old/2.2.11-trdr.md
+++ /dev/null
@@ -1,25 +0,0 @@
-# 2.2.11. <span class="pho">tr/dr</span>
-
-<span class="pho">tr/dr</span> 和 <span class="pho">tʃ/dʒ</span> 不一样的地方在于，虽然发声时起始的舌尖位置相同，但，<span class="pho">tr, dr</span> 在发声之前嘴唇要有个缩小成圆形的动作，所以它们开头的音节，总是听起来夹带着一个 <span class="pho">w</span>，*tree* <span class="pho">/triː</span>/ 听起来是 <span class="pho alt">tʃwiː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/tree-us.mp3" data-audio-uk-male="/audios/us/tree-uk.mp3"></span>，*dry* <span class="pho alt">draɪ</span> 听起来是 <span class="pho alt">dʒwaɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/dry-us.mp3" data-audio-uk-male="/audios/us/dry-uk.mp3"></span>。
-
-The difference between the sounds <span class="pho">tr, dr</span> and <span class="pho">tʃ, dʒ</span> lies in the way they are pronounced. Although the initial tongue position is the same for both sets of sounds, with <span class="pho">tr, dr</span>, there's a slight rounding of the lips before voicing. As a result, the starting syllables often sound as if there's a <span class="pho">w</span> blended in. So, the word *tree* <span class="pho alt">triː</span> can sound like <span class="pho alt">tʃwiː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/tree-us.mp3" data-audio-uk-male="/audios/us/tree-uk.mp3"></span>, and *dry* <span class="pho alt">draɪ</span> can sound like <span class="pho alt">dʒwaɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/dry-us.mp3" data-audio-uk-male="/audios/us/dry-uk.mp3"></span>.
-
-很多地区的人基于自身母语的习惯，会把 <span class="pho">tr</span> 和 <span class="pho">dr</span> 分开着连续读出的。比如，*tree*，印度人可能会把它读成 <span class="pho alt">tɤ.riː</span><span class="speak-word-inline" data-audio-other="/audios/us/tree-ru-ru.mp3"></span>，其中的 <span class="pho">t</span> 干脆读成 <span class="pho">d</span>，并且 <span class="pho">r</span> 还会用齿龈颤音；再比如，*driver*，可能会被俄罗斯人读成 <span class="pho alt">dɤ.raɪvə</span><span class="speak-word-inline" data-audio-other="/audios/us/driver-ru-ru.mp3"></span>，其中的 <span class="pho">r</span> 同样会用齿龈颤音。
-
-People from many regions, guided by the habits of their native languages, may pronounce <span class="pho">tr</span> and <span class="pho">dr</span> as separate, continuous sounds. For instance, someone from India might pronounce *tree* as <span class="pho alt">tɤ.riː</span><span class="speak-word-inline" data-audio-other="/audios/us/tree-ru-ru.mp3"></span>, with the <span class="pho">t</span> articulated as <span class="pho">d</span>, and the <span class="pho">r</span> as a [*voiced alveolar trill*](https://en.wikipedia.org/wiki/Voiced_dental,_alveolar_and_postalveolar_trills). Similarly, the word *driver* might be pronounced as <span class="pho alt">dɤ.raɪvə</span><span class="speak-word-inline" data-audio-other="/audios/us/driver-ru-ru.mp3"></span> by a Russian speaker, again using a voiced alveolar trill for the <span class="pho">r</span>.
-
-## 拼写（Spellings）
-
-### <span class="pho">tr</span>
-
-* **tr**
-  * track <span class="pho alt">træk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/track-us-male.mp3" data-audio-us-female="/audios/us/track-us-female.mp3"></span>
-  * tree <span class="pho alt">triː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/tree-us-male.mp3" data-audio-us-female="/audios/us/tree-us-female.mp3"></span>
-  * trick <span class="pho alt">trɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/trick-us-male.mp3" data-audio-us-female="/audios/us/trick-us-female.mp3"></span>
-
-### <span class="pho">dr</span>
-
-* **dr**
-  * drive <span class="pho alt">draɪv</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/drive-us-male.mp3" data-audio-us-female="/audios/us/drive-us-female.mp3"></span>
-  * dream <span class="pho alt">driːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/dream-us-male.mp3" data-audio-us-female="/audios/us/dream-us-female.mp3"></span>
-  * drink <span class="pho alt">drɪŋk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/drink-us-male.mp3" data-audio-us-female="/audios/us/drink-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.2.12-tsdz.md b/1000-hours/sounds-of-american-english-old/2.2.12-tsdz.md
deleted file mode 100644
index 88a3bd29..00000000
--- a/1000-hours/sounds-of-american-english-old/2.2.12-tsdz.md
+++ /dev/null
@@ -1,27 +0,0 @@
-# 2.2.12. <span class="pho">ts/dz</span>
-
-<span class="pho">ts/dz</span> 和 <span class="pho">s/z</span> 不一样的地方在于发声时起始的舌尖位置，<span class="pho">s/z</span> 起始的舌尖位置贴近但没有接触到牙齿和牙龈的接缝处；但，<span class="pho">ts/dz</span> 的舌尖要再往后一点，和 <span class="pho">t/d</span> 发声时起始的舌尖位置一样，贴在龈脊的那个部位之后开始发声。
-
-The difference between <span class="pho">ts/dz</span> and <span class="pho">s/z</span> lies in the initial tongue position during pronunciation. For <span class="pho">s/z</span>, the tip of the tongue is close to, but not touching, the *seam* of the teeth and gums. However, for <span class="pho">ts/dz</span>, the tongue tip is a bit further back, identical to the initial position when pronouncing <span class="pho">t/d</span>. It starts pronouncing from that spot of the *alveolar ridge*.
-
-![articulator-tongue-tip-td](/images/articulator-tongue-tip-td.svg)
-
-可以用 *students* <span class="pho alt">ˈstudənts</span><span class="speak-word-inline" data-audio-us-male="/audios/us/students-us-male.mp3" data-audio-us-female="/audios/us/students-us-female.mp3"></span> 这个词反复体会 <span class="pho">s</span>、<span class="pho">d</span>、<span class="pho">ts</span> 的舌尖位置（注意，开头的 <span class="pho">st</span> 会被读成 <span class="pho">sd</span>）……
-
-The word *students* <span class="pho alt">ˈstudənts</span><span class="speak-word-inline" data-audio-us-male="/audios/us/students-us-male.mp3" data-audio-us-female="/audios/us/students-us-female.mp3"></span> can be repeatedly pronounced to understand the tongue positions for <span class="pho">s</span>, <span class="pho">d</span>, and <span class="pho">ts</span> (note that the initial <span class="pho">st</span> is pronounced like <span class="pho">sd</span>).
-
-## 拼写（Spellings）
-
-### <span class="pho">ts</span>
-
-* **ts**
-  * clients <span class="pho alt">ˈklaɪ.ənts</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/clients-us-male.mp3" data-audio-us-female="/audios/us/clients-us-female.mp3"></span>
-  * students <span class="pho alt">ˈstuː.dənts</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/students-us-male.mp3" data-audio-us-female="/audios/us/students-us-female.mp3"></span>
-  * treats <span class="pho alt">triːts</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/treats-us-male.mp3" data-audio-us-female="/audios/us/treats-us-female.mp3"></span>
-
-### <span class="pho">dz</span>
-
-* **ds**
-  * deeds <span class="pho alt">diːdz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/deeds-us-male.mp3" data-audio-us-female="/audios/us/deeds-us-female.mp3"></span>
-  * records <span class="pho alt">rɪˈkɔːrdz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/records-us-male.mp3" data-audio-us-female="/audios/us/records-us-female.mp3"></span>
-  * words <span class="pho alt">wɝːdz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/words-us-male.mp3" data-audio-us-female="/audios/us/words-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.2.13-mnŋ.md b/1000-hours/sounds-of-american-english-old/2.2.13-mnŋ.md
deleted file mode 100644
index 34bfe746..00000000
--- a/1000-hours/sounds-of-american-english-old/2.2.13-mnŋ.md
+++ /dev/null
@@ -1,57 +0,0 @@
-# 2.2.13. <span class="pho">m</span>, <span class="pho">n</span>, <span class="pho">ŋ</span>
-
-<span class="pho">m</span> 和 <span class="pho">n</span> 处于音节开头时，没有人会觉得困难。尤其是 <span class="pho">m</span>…… 因为它也许是人类学会说的第一个辅音；于此同时，<span class="pho">ɑ</span> 永远是人类学会的第一个元音，所以大家都用 <span class="pho">mɑ</span> 称呼自己的母亲。
-
-When <span class="pho">m</span> and <span class="pho">n</span> are at the beginning of a syllable, no one finds it challenging. Especially <span class="pho">m</span>, since it might be the first consonant humans learn to utter. At the same time, <span class="pho">ɑ</span> is always the first vowel humans learn, which is why <span class="pho">mɑ</span> is a universal sound for *mother*.
-
-<span class="pho">ŋ</span> 处于其它元音之后对所有人来说也同样不构成困难，因为英文中最常用的不过是 <span class="pho">ɪŋ</span>  而已……
-
-Similarly, everyone finds it easy to pronounce <span class="pho">ŋ</span> after other vowels. This isn't surprising, given that <span class="pho">ɪŋ</span> is the most commonly used sounds in English.
-
-麻烦在于 <span class="pho">m</span> 处于音节末尾的时候。很多人会不由自主地额外加上一个 <span class="pho">ʊ</span> 的音，这是一个嘴唇的多余动作产生的结果。比如，把 *room* <span class="pho alt">ruːm</span> 读成 <span class="pho alt">ruːmʊ</span>。
-
-The tricky part comes when <span class="pho">m</span> is at the end of a syllable. A lot of people have an involuntary habit of adding an extra <span class="pho">ʊ</span> sound, which results from an unnecessary lips' movement. For instance, they might pronounce *room* as <span class="pho alt">ruːmʊ</span>, instead of <span class="pho alt">ruːm</span>.
-
-当 <span class="pho">m/n</span> 处于 <span class="pho">f/v</span> 之前的时候，发音都会发生变化 —— 这是因为 <span class="pho">f/v</span> 的发声动作，需要上牙与下唇接触。
-
-When <span class="pho">m/n</span> precedes <span class="pho">f/v</span>, their pronunciation changes - this is because the vocalization of <span class="pho">f/v</span> requires the upper teeth to touch the lower lip.
-
-> * <span class="pho">m + f/v</span> = <span class="pho">n + f/v</span>, *comfort* <span class="pho alt">ˈkəmfərt</span> → <span class="pho alt">ˈkənfərt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/comfort-us-male.mp3" data-audio-us-female="/audios/us/comfort-us-female.mp3"></span>
-> * <span class="pho">n + f/v</span> = <span class="pho">ŋ + f/v</span>, *conversation* <span class="pho alt">ˌkɑnvərˈseɪʃən</span> → <span class="pho alt">ˌkɑŋvərˈseɪʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/conversation-us-male.mp3" data-audio-us-female="/audios/us/conversation-us-female.mp3"></span>
-
-另外，当 <span class="pho">æ</span> 在 <span class="pho">m</span> 之前的时候，部分母语使用者会添一个 <span class="pho">ə</span> 进去，比如，Sam <span class="pho alt">sæm</span><span class="speak-word-inline" data-audio-us-male="/audios/us/sam-us-male.mp3" data-audio-us-female="/audios/us/sam-us-female.mp3"></span>，会被他们读成 <span class="pho alt">sæəm</span>。
-
-Additionally, when the vowel sound <span class="pho">æ</span> comes before <span class="pho">m</span>, some native speakers add an extra <span class="pho">ə</span> sound. For example, *Sam* <span class="pho alt">sæm</span><span class="speak-word-inline" data-audio-us-male="/audios/us/sam-us-male.mp3" data-audio-us-female="/audios/us/sam-us-female.mp3"></span> can sometimes be pronounced as <span class="pho alt">sæəm</span>.
-
-## 拼写（Spellings）
-
-### <span class="pho">m</span>
-
-* **m**
-  * army <span class="pho alt">ˈɑːr.mi</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/army-us-male.mp3" data-audio-us-female="/audios/us/army-us-female.mp3"></span>
-  * mob <span class="pho alt">mɑːb</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/mob-us-male.mp3" data-audio-us-female="/audios/us/mob-us-female.mp3"></span>
-  * mom <span class="pho alt">mɑːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/mom-us-male.mp3" data-audio-us-female="/audios/us/mom-us-female.mp3"></span>
-
-### <span class="pho">n</span>
-
-* **n**
-  * mind <span class="pho alt">maɪnd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/mind-us-male.mp3" data-audio-us-female="/audios/us/mind-us-female.mp3"></span>
-  * night <span class="pho alt">naɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/night-us-male.mp3" data-audio-us-female="/audios/us/night-us-female.mp3"></span>
-  * nine <span class="pho alt">naɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/nine-us-male.mp3" data-audio-us-female="/audios/us/nine-us-female.mp3"></span>
-* **kn**
-  * know <span class="pho alt">noʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/know-us-male.mp3" data-audio-us-female="/audios/us/know-us-female.mp3"></span>
-  * knight <span class="pho alt">naɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/knight-us-male.mp3" data-audio-us-female="/audios/us/knight-us-female.mp3"></span>
-* **gn**
-  * gnaw <span class="pho alt">nɑː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/gnaw-us-male.mp3" data-audio-us-female="/audios/us/gnaw-us-female.mp3"></span>
-  * gnome <span class="pho alt">noʊm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/gnome-us-male.mp3" data-audio-us-female="/audios/us/gnome-us-female.mp3"></span>
-
-### <span class="pho">ŋ</span>
-
-* **n** (before <span class=**pho**>k</span>)
-  * anchor <span class="pho alt">ˈæŋ.kɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/anchor-us-male.mp3" data-audio-us-female="/audios/us/anchor-us-female.mp3"></span>
-  * bank <span class="pho alt">bæŋk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bank-us-male.mp3" data-audio-us-female="/audios/us/bank-us-female.mp3"></span>
-  * thank <span class="pho alt">θæŋk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/thank-us-male.mp3" data-audio-us-female="/audios/us/thank-us-female.mp3"></span>
-* **ng**
-  * bang <span class="pho alt">bæŋ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bang-us-male.mp3" data-audio-us-female="/audios/us/bang-us-female.mp3"></span>
-  * long <span class="pho alt">lɑːŋ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/long-us-male.mp3" data-audio-us-female="/audios/us/long-us-female.mp3"></span>
-  * sing <span class="pho alt">sɪŋ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sing-us-male.mp3" data-audio-us-female="/audios/us/sing-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.2.14-lr.md b/1000-hours/sounds-of-american-english-old/2.2.14-lr.md
deleted file mode 100644
index f7d30d7e..00000000
--- a/1000-hours/sounds-of-american-english-old/2.2.14-lr.md
+++ /dev/null
@@ -1,80 +0,0 @@
-# 2.2.14. <span class="pho">l</span>, <span class="pho">r</span>
-
-<span class="pho">l</span> 发声时起始的舌尖位置与 <span class="pho">t/d</span> 相同 —— 即，位置 ③（参见 [1.4](1.4-articulators)）。
-
-When pronouncing the 'l' sound, the tip of the tongue starts in the same position as it does for 't/d', i.e. position ③ (as described in [1.4](1.4-articulators)).
-
-![articulator-tongue-tip-td](/images/articulator-tongue-tip-td.svg)
-
-<span class="pho">r</span> 发声时起始的舌尖位置相对更加靠后 —— 即，位置 ④（参见 [1.4](1.4-articulators)）
-
-For the 'r' sound, the tongue's tip begins a bit further back, i.e. position ④ (as described in [1.4](1.4-articulators)).
-
-![articulator-tongue-tip-r](/images/articulator-tongue-tip-r.svg)
-
-<span class="pho">l</span> 和 <span class="pho">r</span> 处于音节开头的时候，人们一般不会觉得困难，比如 *lot* <span class="pho alt">lɑːt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/lot-us-male.mp3" data-audio-us-female="/audios/us/lot-us-female.mp3"></span> 或者 *rot* <span class="pho alt">rɑːt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/rot-us-male.mp3" data-audio-us-female="/audios/us/rot-us-female.mp3"></span>……
-
-Pronouncing <span class="pho">l</span> and <span class="pho">r</span> at the beginning of syllables usually is of no difficulty at all, for example in words like *lot*' <span class="pho alt">lɑːt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/lot-us-male.mp3" data-audio-us-female="/audios/us/lot-us-female.mp3"></span> or *rot* <span class="pho alt">rɑːt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/rot-us-male.mp3" data-audio-us-female="/audios/us/rot-us-female.mp3"></span>…
-
-<span class="pho">l</span> 的困难总是来自于它们处在音节末尾的时候。
-
-The difficulty with <span class="pho">l</span> often arises when it's at the end of a syllable.
-
-不妨尝试着先读一下 *milk* <span class="pho alt">mɪlk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/milk-us-male.mp3" data-audio-us-female="/audios/us/milk-us-female.mp3"></span>…… 很多人读出来的实际上是 <span class="pho alt">mjʊk</span>……
-
-Feel free to give the word *milk* <span class="pho alt">mɪlk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/milk-us-male.mp3" data-audio-us-female="/audios/us/milk-us-female.mp3"></span> a try... Many people actually pronounce it more like <span class="pho alt">mjʊk</span>...
-
-<span class="pho">l</span> 在音节末尾的时候，有一个看不到的动作，舌尖会向前向上移动直至贴到龈脊。于是，音节末尾的 <span class="pho">l</span> 会掺杂着一个轻微的 <span class="pho">ə</span> 的元音音色。
-
-There's a hidden motion when the <span class="pho">l</span> is at the end of a syllable. The tip of the tongue moves forward and upward until it touches the *alveolar ridge*. Therefore, the <span class="pho">l</span> at the end of a syllable has a slight vowel sound <span class="pho">ə</span>  mixed in.
-
-说实话，倒也不是特别难，这只不过是几分钟就可以解决的问题。
-
-Actually, it's not too challenging. With just a few minutes, it can be easily corrected.
-
-> * 先反复说 <span class="pho">ə... əl... ə... əl...</span> 这里格外需要注意：嘴唇张开之后没有其它动作，**不要带嘴唇变化造成的 <span class="pho">ʊ</span> 的音色**；从 <span class="pho">ə</span> 到 <span class="pho">l</span> 的过程中，保持声带振动，剩余的全靠舌尖移动完成……
-> * Start by repeating <span class="pho">ə... əl... ə... əl...</span> Here's a crucial point: after opening lips, make *no* other movements. Avoid adding the sound of <span class="pho">ʊ</span> caused by lip changes. During the transition from <span class="pho">ə</span> to <span class="pho">əl</span>, while maintaining vocal cord vibration, let the tip of your tongue handle the rest...
-> * 接着直接反复说 <span class="pho">əl... əl...</span>
-> * Next, repeating <span class="pho">əl... əl...</span>
-> * 再反复说 <span class="pho">əlk... əlk...</span>
-> * Follow with repeating <span class="pho">əlk... əlk...</span>
-> * 现在反复说 <span class="pho">mɪəlk... mɪəlk...</span> 现在需要格外注意：为了 <span class="pho">m</span> 发声所以需要张开嘴唇，但，**此后嘴唇没有其他动作，否则会带着 <span class="pho">ʊ</span> 的音色**……
-> * Now, keep saying <span class="pho">mɪəlk... mɪəlk...</span>. Again, pay special attention here: lips are opened to make the <span class="pho">m</span> sound, but after that, there should be no other lip movement, thus avoiding unnecessary <span class="pho">ʊ</span> sound.
-
-再用同样的方式练练 *girl* <span class="pho alt">ɡɝːl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/girl-us-male.mp3" data-audio-us-female="/audios/us/girl-us-female.mp3"></span>（常常会被误读成 <span class="pho alt">gəʊ</span>）, *world* <span class="pho alt">wɝːld</span><span class="speak-word-inline" data-audio-us-male="/audios/us/world-us-male.mp3" data-audio-us-female="/audios/us/world-us-female.mp3"></span>（常常会被误读成 <span class="pho alt">wəʊd</span>）。
-
-Practice pronouncing *girl* <span class="pho alt">ɡɝːl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/girl-us-male.mp3" data-audio-us-female="/audios/us/girl-us-female.mp3"></span> (often mispronounced as <span class="pho alt">gəʊl</span>) and *world* <span class="pho alt">wɝːld</span><span class="speak-word-inline" data-audio-us-male="/audios/us/world-us-male.mp3" data-audio-us-female="/audios/us/world-us-female.mp3"></span> (often mispronounced as <span class="pho alt">wəʊd</span>) the same way.
-
-以 <span class="pho">l</span> 处于音节末尾的常用词汇很多，读得时候要注意，要加上 <span class="pho">ə</span>，比如：
-
-There are many common words where <span class="pho">l</span> ends the syllable. Be sure to include the <span class="pho">ə</span> sound when pronouncing them. For example:
-
-> *fail* <span class="pho alt">feɪl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/fail-us-male.mp3" data-audio-us-female="/audios/us/fail-us-female.mp3"></span>, *file* <span class="pho alt">faɪl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/file-us-male.mp3" data-audio-us-female="/audios/us/file-us-female.mp3"></span>, *sell* <span class="pho alt">sel</span><span class="speak-word-inline" data-audio-us-male="/audios/us/sell-us-male.mp3" data-audio-us-female="/audios/us/sell-us-female.mp3"></span>, *sale* <span class="pho alt">seɪl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/sale-us-male.mp3" data-audio-us-female="/audios/us/sale-us-female.mp3"></span>, *tell* <span class="pho alt">tel</span><span class="speak-word-inline" data-audio-us-male="/audios/us/tell-us-male.mp3" data-audio-us-female="/audios/us/tell-us-female.mp3"></span>, *tale* <span class="pho alt">teɪl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/tale-us-male.mp3" data-audio-us-female="/audios/us/tale-us-female.mp3"></span>, *trail* <span class="pho alt">treɪl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/trail-us-male.mp3" data-audio-us-female="/audios/us/trail-us-female.mp3"></span>, *drill* <span class="pho alt">drɪl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/drill-us-male.mp3" data-audio-us-female="/audios/us/drill-us-female.mp3"></span>...
-
-注意，<span class="pho alt">ʌl</span> 没有 <span class="pho">ᵊ</span> 的加音，因为 <span class="pho">ʌ</span> 和 <span class="pho">ə</span> 原本就非常相近。比如，*ultimate* <span class="pho alt">ˈʌltɪmət</span><span class="speak-word-inline" data-audio-us-male="/audios/us/ultimate-us-male.mp3" data-audio-us-female="/audios/us/ultimate-us-female.mp3"></span>，或者 *result* <span class="pho alt">rɪˈzəlt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/result-us-male.mp3" data-audio-us-female="/audios/us/result-us-female.mp3"></span>。另外，在自然语音中，<span class="pho alt">iːl</span> 要注意。比如， *reveal*，词典里的音标是 <span class="pho alt">rɪˈviːl</span>， 但它的确读做 <span class="pho alt">rɪˈviːᵊl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/reveal-us-male.mp3" data-audio-us-female="/audios/us/reveal-us-female.mp3"></span>，有加音 <span class="pho">ᵊ</span>，但，*revealing*，读作 <span class="pho alt">rɪˈviːlɪŋ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/revealing-us-male.mp3" data-audio-us-female="/audios/us/revealing-us-female.mp3"></span>，没有加音 <span class="pho">ᵊ</span>，可能是因为 <span class="pho">l</span> 被挪到后面和 <span class="pho">ɪŋ</span> 构成了第三个音节 <span class="pho alt">lɪŋ</span>……
-
-Note that <span class="pho alt">ʌl</span> doesn't have  <span class="pho">ᵊ</span> sound added, since <span class="pho alt">ʌ</span> and <span class="pho">ə</span> are already very similar. For instance, *ultimate* <span class="pho alt">ˈəltəmət</span><span class="speak-word-inline" data-audio-us-male="/audios/us/ultimate-us-male.mp3" data-audio-us-female="/audios/us/ultimate-us-female.mp3"></span>, or *result* <span class="pho alt">rɪˈzəlt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/result-us-male.mp3" data-audio-us-female="/audios/us/result-us-female.mp3"></span>. Also, pay attention to <span class="pho alt">iːl</span> in natural speech. For example, while *reveal* is noted as <span class="pho alt">rɪˈviːl</span> in dictionary, and indeed pronounced as <span class="pho alt">rɪˈviːᵊl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/reveal-us-male.mp3" data-audio-us-female="/audios/us/reveal-us-female.mp3"></span>, with <span class="pho">ᵊ</span> sound, *revealing* is pronounced as <span class="pho alt">rɪˈviːlɪŋ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/revealing-us-male.mp3" data-audio-us-female="/audios/us/revealing-us-female.mp3"></span>, without <span class="pho">ᵊ</span>. This change might be due to the fact that the <span class="pho">l</span> sound has been moved to form a third syllable with <span class="pho">ɪŋ</span> as <span class="pho alt">lɪŋ</span>.
-
-<span class="pho">l</span> 在语言学里有个专门的称呼，叫做**音节辅音**，就是因为它的发声动作如果完整的话，前面就会自然附加着一个轻微的元音 <span class="pho">ᵊ</span> 的音色。比如，*little* <span class="pho alt">ˈlɪtl̩</span><span class="speak-word-inline" data-audio-us-male="/audios/us/little-us-male.mp3" data-audio-us-female="/audios/us/little-us-female.mp3"></span> —— <span class="pho">l</span> 下面多出的那一个点 <span class="pho">l̩</span> 的意思是说，这里的 <span class="pho">l̩</span> 是个**音节辅音**，相当于 <span class="pho alt">ᵊl</span>…… 当然，很多词典干脆就直接标注成了 <span class="pho alt">ˈlɪtᵊl</span> 或者 <span class="pho alt">ˈlɪtəl</span>。CEPD 里标注的是 <span class="pho alt">ˈlɪt̬əl</span>，因为 <span class="pho">t</span> 夹在两个元音之间，变成了弹舌音 <span class="pho">t̬</span>。
-
-In linguistics, the letter <span class="pho">l</span> has a particular name - it's called a *syllabic consonant*. This is because when it is fully pronounced, a subtle vowel sound <span class="pho">ᵊ</span> naturally attaches to the front of it. For example, in the word *little* <span class="pho alt">ˈlɪtl̩</span><span class="speak-word-inline" data-audio-us-male="/audios/us/little-us-male.mp3" data-audio-us-female="/audios/us/little-us-female.mp3"></span>, the dot under the <span class="pho">l</span> (<span class="pho">l̩</span>) indicates that this <span class="pho">l</span> is a *syllabic consonant*. It's equivalent to <span class="pho alt">ᵊl</span>. And many dictionaries simply denote it as <span class="pho alt">ˈlɪtəl</span>. The pronunciation indicated in the CEPD is <span class="pho alt">ˈlɪt̬əl</span>, for the <span class="pho">t</span> is sandwiched between two vowels, which in this case becomes a flapped <span class="pho">t̬</span>.
-
-英文中另外一个**音节辅音**是 <span class="pho">m</span>。例如，*chasm* <span class="pho alt">ˈkæzm̩</span><span class="speak-word-inline" data-audio-us-male="/audios/us/chasm-us-male.mp3" data-audio-us-female="/audios/us/chasm-us-female.mp3"></span>，相当于 <span class="pho alt">ˈkæzᵊm</span>, *prism* <span class="pho alt">ˈprɪzm̩</span><span class="speak-word-inline" data-audio-us-male="/audios/us/prism-us-male.mp3" data-audio-us-female="/audios/us/prism-us-female.mp3"></span>，相当于 <span class="pho alt">ˈprɪzᵊm</span>。
-
-Another *syllabic consonant* in English is <span class="pho">m</span>. For example, *chasm* <span class="pho alt">ˈkæzm̩</span><span class="speak-word-inline" data-audio-us-male="/audios/us/chasm-us-male.mp3" data-audio-us-female="/audios/us/chasm-us-female.mp3"></span>，equivalent to <span class="pho alt">ˈkæzᵊm</span>, and *prism* <span class="pho alt">ˈprɪzm̩</span><span class="speak-word-inline" data-audio-us-male="/audios/us/prism-us-male.mp3" data-audio-us-female="/audios/us/prism-us-female.mp3"></span>，equivalent to <span class="pho alt">ˈprɪzᵊm</span>.
-
-## 拼写（Spellings）
-
-### <span class="pho">l</span>
-
-* **l**
-  * feel <span class="pho alt">fiːl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/feel-us-male.mp3" data-audio-us-female="/audios/us/feel-us-female.mp3"></span>
-  * like <span class="pho alt">laɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/like-us-male.mp3" data-audio-us-female="/audios/us/like-us-female.mp3"></span>
-  * mill <span class="pho alt">mɪl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/mill-us-male.mp3" data-audio-us-female="/audios/us/mill-us-female.mp3"></span>
-
-### <span class="pho">r</span>
-
-* **r**
-  * read <span class="pho alt">riːd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/read-us-male.mp3" data-audio-us-female="/audios/us/read-us-female.mp3"></span>
-  * road <span class="pho alt">roʊd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/road-us-male.mp3" data-audio-us-female="/audios/us/road-us-female.mp3"></span>
-  * ring <span class="pho alt">rɪŋ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/ring-us-male.mp3" data-audio-us-female="/audios/us/ring-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.2.15-wj.md b/1000-hours/sounds-of-american-english-old/2.2.15-wj.md
deleted file mode 100644
index c69e5e54..00000000
--- a/1000-hours/sounds-of-american-english-old/2.2.15-wj.md
+++ /dev/null
@@ -1,43 +0,0 @@
-# 2.2.15. <span class="pho">j</span>, <span class="pho">w</span>
-
-<span class="pho">j</span> 和 <span class="pho">w</span> 是半元音。
-
-The sounds represented by <span class="pho">j</span> and <span class="pho">w</span> are semivowels in English.
-
-<span class="pho">j</span> 与后面的元音相连，相当于在那个元音前面加上了一个 <span class="pho">ɪ</span>，比如 *you* <span class="pho alt">juː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/you-us-male.mp3" data-audio-us-female="/audios/us/you-us-female.mp3"></span>，读音上相当于是 <span class="pho alt">iuː</span>。
-
-When <span class="pho">j</span> is connected to the following vowel, it is as if an <span class="pho">ɪ</span> sound is added in front of that vowel. For instance, the word *you* <span class="pho alt">juː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/you-us-male.mp3" data-audio-us-female="/audios/us/you-us-female.mp3"></span>, pronounced the same as <span class="pho alt">ɪuː</span>.
-
-<span class="pho">w</span> 与后面的元音相连，相当于在那个元音前面加上了一个 <span class="pho">ʊ</span>，比如 *way* <span class="pho">weɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/way-us-male.mp3" data-audio-us-female="/audios/us/way-us-female.mp3"></span>，读音上相当于是 <span class="pho">ʊeɪ</span>。
-
-Similarly, when <span class="pho">w</span> is paired with a vowel, it's as if a <span class="pho">ʊ</span> sound precedes that vowel. Take the word *way* <span class="pho alt">weɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/way-us-male.mp3" data-audio-us-female="/audios/us/way-us-female.mp3"></span>, pronounced the same as <span class="pho alt">ʊeɪ</span>.
-
-<span class="pho">w</span> 可以和另外的辅音结合作为音节开头：<span class="pho">sw</span>、<span class="pho">tw</span>、<span class="pho">dw</span>、<span class="pho">kw</span>、<span class="pho">skw</span>、<span class="pho">gw</span>…… 这其中最容易出错也最常的是 <span class="pho">kw</span>，尤其是 <span class="pho">kwɒ</span> 和 <span class="pho">kwɔː</span>，比如，*quart* <span class="pho alt">kwɔːrt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/quart-us-male.mp3" data-audio-us-female="/audios/us/quart-us-female.mp3"></span>，常常会被误读为 <span class="pho alt">kɔːrt</span>（听起来和 *court* <span class="pho alt">kɔːrt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/court-us-male.mp3" data-audio-us-female="/audios/us/court-us-female.mp3"></span> 同音）；再比如，*quality* <span class="pho alt">ˈkwɔːlɪti</span><span class="speak-word-inline" data-audio-us-male="/audios/us/quality-us-male.mp3" data-audio-us-female="/audios/us/quality-us-female.mp3"></span> 常常会被误读为 <span class="pho alt">ˈkɔːlɪti</span> —— 关键在于，<span class="pho">k</span> 的音之后有一个发出 <span class="pho">ʊ</span> 的嘴唇动作，否则 <span class="pho">kw</span> 就变成了 <span class="pho">k</span> —— 这个差异在母语使用者听起来异常地明显。
-
-The letter <span class="pho">w</span> can combine with other consonants to form the beginning of a syllable, such as <span class="pho">sw</span>, <span class="pho">tw</span>, <span class="pho">dw</span>, <span class="pho">kw</span>, <span class="pho">skw</span>, <span class="pho">gw</span>… The most common and often mispronounced combination is <span class="pho">kw</span>, specifically <span class="pho">kwɒ</span> and <span class="pho">kwɔː</span>. For example, the word *quart* is pronounced <span class="pho alt">kwɔːrt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/quart-us-male.mp3" data-audio-us-female="/audios/us/quart-us-female.mp3"></span>, but it is often misconstrued as <span class="pho alt">kɔːrt</span>, which sounds like *court* <span class="pho alt">kɔːrt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/court-us-male.mp3" data-audio-us-female="/audios/us/court-us-female.mp3"></span>, or *quality* <span class="pho alt">ˈkwɔːlɪti</span><span class="speak-word-inline" data-audio-us-male="/audios/us/quality-us-male.mp3" data-audio-us-female="/audios/us/quality-us-female.mp3"></span> as <span class="pho alt">ˈkɔːlɪti</span>. The key to getting this right is to make a lip movement for the <span class="pho">ʊ</span> sound after the <span class="pho">k</span> sound; otherwise, <span class="pho">kw</span> just becomes <span class="pho">k</span>. This distinction is incredibly noticeable to native speakers.
-
-## 拼写（Spellings）
-
-### <span class="pho">w</span>
-
-* **w**
-  * week <span class="pho alt">wiːk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/week-us-male.mp3" data-audio-us-female="/audios/us/week-us-female.mp3"></span>
-  * weird <span class="pho alt">wɪrd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/weird-us-male.mp3" data-audio-us-female="/audios/us/weird-us-female.mp3"></span>
-  * wife <span class="pho alt">waɪf</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/wife-us-male.mp3" data-audio-us-female="/audios/us/wife-us-female.mp3"></span>
-* **wh**
-  * white <span class="pho alt">waɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/white-us-male.mp3" data-audio-us-female="/audios/us/white-us-female.mp3"></span>
-  * what <span class="pho alt">wɑːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/what-us-male.mp3" data-audio-us-female="/audios/us/what-us-female.mp3"></span>
-  * why <span class="pho alt">waɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/why-us-male.mp3" data-audio-us-female="/audios/us/why-us-female.mp3"></span>
-
-### <span class="pho">j</span>
-
-* **y**
-  * yes <span class="pho alt">jes</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/yes-us-male.mp3" data-audio-us-female="/audios/us/yes-us-female.mp3"></span>
-  * yet <span class="pho alt">jet</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/yet-us-male.mp3" data-audio-us-female="/audios/us/yet-us-female.mp3"></span>
-  * yoke <span class="pho alt">joʊk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/yoke-us-male.mp3" data-audio-us-female="/audios/us/yoke-us-female.mp3"></span>
-* **i**
-  * onion <span class="pho alt">ˈʌn.jən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/onion-us-male.mp3" data-audio-us-female="/audios/us/onion-us-female.mp3"></span>
-  * million <span class="pho alt">ˈmɪl.jən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/million-us-male.mp3" data-audio-us-female="/audios/us/million-us-female.mp3"></span>
-* **j**
-  * jager <span class="pho alt">ˈjeɪ.ɡɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/jager-us-male.mp3" data-audio-us-female="/audios/us/jager-us-female.mp3"></span>
-  * hallelujah <span class="pho alt">ˌhæl.ɪˈluː.jə</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/hallelujah-us-male.mp3" data-audio-us-female="/audios/us/hallelujah-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.2.2-pb.md b/1000-hours/sounds-of-american-english-old/2.2.2-pb.md
deleted file mode 100644
index a357ce3e..00000000
--- a/1000-hours/sounds-of-american-english-old/2.2.2-pb.md
+++ /dev/null
@@ -1,40 +0,0 @@
-# 2.2.2 <span class="pho">p/b</span>
-
-<span class="pho">p/b</span> 的发声动作一样，都是先把嘴唇闭合，而后用气流冲开嘴唇。<span class="pho">p</span> 没有声带振动，而 <span class="pho">b</span> 有声带振动。
-
-The pronunciation of <span class="pho">p</span> and <span class="pho">b</span> share the same mechanism, where the lips first close, then air pressure forces them apart. The difference lies in the vibration of the vocal cords: <span class="pho">p</span> doesn't involve vocal cord vibration, while <span class="pho">b</span> does.
-
-这两个辅音都会自然带有很轻微的 <span class="pho">ʊ</span> 的音色 —— 是气流冲开嘴唇自然产生的声音。
-
-Both consonants naturally have a slight <span class="pho">ʊ</span> sound, which is a byproduct of the air bursting past lips.
-
-中国学生在起初的时候常常分不清 *please* 和 *police* —— 可事实上，这两个词的区别很明显，区别很多：
-
-Chinese students often struggle to distinguish between *please* and *police* at first when learning English. But they are distinctly different, and with many differences:
-
-* *please* 只有一个音节：<span class="pho alt">pliːz</span><span class="speak-word-inline" data-audio-us-male="/audios/us/please-us-male.mp3" data-audio-us-female="/audios/us/please-us-female.mp3"></span>，而 *police* 有两个音节： <span class="pho alt">pəˈliːs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/police-us-male.mp3" data-audio-us-female="/audios/us/police-us-female.mp3"></span>；
-* *please* consists of a single syllable: <span class="pho alt">pliːz</span><span class="speak-word-inline" data-audio-us-male="/audios/us/please-us-male.mp3" data-audio-us-female="/audios/us/please-us-female.mp3"></span>, while *police* has two syllables: <span class="pho alt">pəˈliːs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/police-us-male.mp3" data-audio-us-female="/audios/us/police-us-female.mp3"></span>.
-* 前者末尾的辅音是 <span class="pho">z</span>，后者末尾的辅音是 <span class="pho">s</span>；
-* The final consonant in *please* is a <span class="pho">z</span> sound, whereas in *police*, it's an <span class="pho">s</span> sound.
-* 最关键的，前者开头最多听起来是 <span class="pho">pʊ</span>，而后者不一样，是 <span class="pho">p</span> 和另外一个元音构成的音节： <span class="pho">pə</span>……
-* Most importantly, the initial sound in *please* might be heard as <span class="pho">pʊ</span>, but in *police*, it's different. It's a syllable composed of <span class="pho">p</span> and another vowel: <span class="pho">pə</span>...
-
-## 拼写（Spellings）
-
-### <span class="pho">p</span>
-
-* **p**
-  * pat <span class="pho alt">pæt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pat-us-male.mp3" data-audio-us-female="/audios/us/pat-us-female.mp3"></span>
-  * pick <span class="pho alt">pɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pick-us-male.mp3" data-audio-us-female="/audios/us/pick-us-female.mp3"></span>
-  * stop <span class="pho alt">stɑːp</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/stop-us-male.mp3" data-audio-us-female="/audios/us/stop-us-female.mp3"></span>
-* **pp**
-  * happy <span class="pho alt">ˈhæp.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/happy-us-male.mp3" data-audio-us-female="/audios/us/happy-us-female.mp3"></span>
-  * hopper <span class="pho alt">ˈhɑː.pɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/hopper-us-male.mp3" data-audio-us-female="/audios/us/hopper-us-female.mp3"></span>
-  * puppet <span class="pho alt">ˈpʌp.ɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/puppet-us-male.mp3" data-audio-us-female="/audios/us/puppet-us-female.mp3"></span>
-
-### <span class="pho">b</span>
-
-* **b**
-  * big <span class="pho alt">bɪɡ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/big-us-male.mp3" data-audio-us-female="/audios/us/big-us-female.mp3"></span>
-  * blob <span class="pho alt">blɑːb</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/blob-us-male.mp3" data-audio-us-female="/audios/us/blob-us-female.mp3"></span>
-  * club <span class="pho alt">klʌb</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/club-us-male.mp3" data-audio-us-female="/audios/us/club-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.2.3-td.md b/1000-hours/sounds-of-american-english-old/2.2.3-td.md
deleted file mode 100644
index 39ce6c36..00000000
--- a/1000-hours/sounds-of-american-english-old/2.2.3-td.md
+++ /dev/null
@@ -1,83 +0,0 @@
-# 2.2.3 <span class="pho">t/d</span>
-
-虽然每种语言都有这两个辅音，但，英文的 <span class="pho">t/d</span> 的发声关键在于起始的舌尖位置 —— 顶在**龈脊**（*alveolar ridge*）上，而不是贴在牙齿上 —— 即，位置 ③（参见 [1.4](1.4-articulators)）。
-
-While every language has the consonants <span class="pho">t</span> and <span class="pho">d</span>, the key to pronouncing them in English lies in the starting position of the tip of the tongue - it should touch the *alveolar ridge*, i.e. position ③ (as described in [1.4](1.4-articulators)), not the *teeth*.
-
-![articulator-tongue-tip-td](/images/articulator-tongue-tip-td.svg)
-
-在中文普通话里，<span class="pho">t/d</span> 这两个声母发声时起始的舌尖位置贴在牙齿上；你可以试着用中文普通话说一遍 “我踢死你！”（<span class="pho">wǒ tī sǐ nǐ</span>）<span class="speak-word-inline" data-audio-other="/audios/us/我踢死你-zh-cn-male.mp3"></span>……
-
-In Mandarin Chinese, the starting position of the tongue tip for the <span class="pho">t</span> and <span class="pho">d</span> sounds rests on the teeth. You can try this out by saying "wǒ tī sǐ nǐ" (我踢死你！)<span class="speak-word-inline" data-audio-other="/audios/us/我踢死你-zh-cn-male.mp3"></span> in Mandarin.
-
-对中国人来说，起初的时候这是个相当难以纠正的习惯，因为舌尖总是不由自主地贴到牙齿上而不是龈脊上 —— 只能通过大量且高密度的练习建立新习惯。
-
-For Chinese speakers, it's a pretty tough to correct at first because the tongue tip instinctively goes to the teeth, not the *alveolar ridge*. It can only be corrected through intense and frequent practice to build a new habit.
-
-另外，就好像 <span class="pho">p/b</span> 在发音的时候会自然带着一个很轻的 <span class="pho">ʊ</span> 一样，<span class="pho">t/d</span> 也会自然带着一个很轻的元音，不过，不是 <span class="pho">ə</span> 而是 <span class="pho">ɤ</span><span class="speak-word-inline" data-audio-other="/audios/us/Close-mid_back_unrounded_vowel.ogg.mp3"></span> —— 之前提到过，相当于中文里 “思念” 的 “思”（<span class="pho">sī</span>）的韵母（[2.1.10](2.1.10-ɤ)）。
-
-Additionally, just as the <span class="pho">p</span> and <span class="pho">b</span> sound naturally carries a slight <span class="pho">ʊ</span> sound in its pronunciation, the <span class="pho">t</span> and <span class="pho">d</span> sound also carries a light vowel sound. But instead of 'ə', it's <span class="pho">ɤ</span><span class="speak-word-inline" data-audio-other="/audios/us/Close-mid_back_unrounded_vowel.ogg.mp3"></span> - as previously mentioned, this is equivalent to the vowel in the Chinese word for 思, which is <span class="pho">sī.</span>
-
-在中文拼音里，<span class="pho">i</span> 在 <span class="pho">t/d</span> 之后相当于英文音标中的 <span class="pho">i</span>；在 <span class="pho">z/c/s</span> 之后的 <span class="pho">i</span> 才会读成 <span class="pho">ɤ</span>…… 所以，依据母语的习惯，中国人习惯于将 <span class="pho">t(ɤ)</span> 读作 <span class="pho">tə</span>，将 <span class="pho">d(ɤ)</span> 读作 <span class="pho">də</span>。需要为此专门建立一个新习惯。
-
-In the Chinese phonetic system, <span class="pho">i</span> following <span class="pho">t/d</span> is similar to <span class="pho">i</span> in English phonetic notation. Meanwhile, <span class="pho">i</span> after <span class="pho">z/c/s</span> is pronounced as <span class="pho">ɤ</span>. So, according to the habits of their native language, Chinese speakers tend to pronounce <span class="pho">t(ɤ)</span> as <span class="pho">tə</span>, and <span class="pho">d(ɤ)</span> as <span class="pho">də</span>. This calls for establishing a new habit.
-
-<span class="pho">t</span> 这个音素，也许是美式英语的辅音里最复杂的一个 —— 当然也是最常用的一个。美式英语中，<span class="pho">t</span> 的变体（allophone）至少有以下几种：
-
-The <span class="pho">t</span> sound may be the most complex in American English consonant pronunciations — and certainly one of the most frequently used. In American English, several variations, or *allophones*, of <span class="pho">t</span> exist:
-
-> * 正常音 <span class="pho">t</span> - 通常是 <span class="pho">t</span> 处于重音音节开头的时候才会被正常读出，比如，*take* <span class="pho alt">teɪk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/take-us-male.mp3" data-audio-us-female="/audios/us/take-us-female.mp3"></span>。
-> * Standard <span class="pho">t</span> - This is the typical pronunciation, when <span class="pho">t</span> begins a stressed syllable, as in *take* <span class="pho alt">teɪk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/take-us-male.mp3" data-audio-us-female="/audios/us/take-us-female.mp3"></span>.
-> * 阻塞音 <span class="pho">t</span> - 处于音节末尾的 <span class="pho">t</span>，有时只是舌尖动作完整，却没有发出声音。即，舌尖顶到龈脊之后并没有送出气流。比如，*cat* <span class="pho alt">kæt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/cat-us-male.mp3" data-audio-us-female="/audios/us/cat-us-female.mp3"></span>。IPA 里有一个专门的标记符号（<span class="pho">◌̚</span>）用来标注发声器官动作完整却没有发声因而产生停顿（*stop*）的辅音（包括 <span class="pho">t/d/p/b/k/g</span>）。比如，*cat* <span class="pho alt">kæt</span> 会被标注成 <span class="pho alt">kæt̚</span>。
-> * Stop <span class="pho">t</span> - This refers to when the <span class="pho">t</span> is at the end of a syllable, often the tongue completes the movement but no sound is actually made. In other words, the tongue touches the ridge of the alveolar ridge but doesn't release a flow of air. An example of this can be found in the word *cat* <span class="pho alt">kæt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/cat-us-male.mp3" data-audio-us-female="/audios/us/cat-us-female.mp3"></span>. And in IPA, there's a specific notation symbol, represented as <span class="pho">◌̚</span>, used to mark consonants like <span class="pho">t/d/p/b/k/g</span> that are fully articulated but not voiced, resulting in a *stop*. For instance, the word *cat*, pronounced as <span class="pho alt">kæt</span>, would be notated as <span class="pho alt">kæt̚</span>.
-> * 弹舌音 <span class="pho">t̬</span> - 夹在两个元音中间的 <span class="pho">t</span> 会变成接近 <span class="pho">d</span> 的弹舌音 <span class="pho">t̬</span>，比如，*water* <span class="pho alt">ˈwɑːt̬ɚ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/water-us-male.mp3" data-audio-us-female="/audios/us/water-us-female.mp3"></span>。
-> * Flaping <span class="pho">t̬</span>: When <span class="pho">t</span> is situated between two vowels, it tends to be flaping <span class="pho">t̬</span>, sounding like <span class="pho">d</span>, as in water <span class="pho alt">ˈwɑːt̬ɚ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/water-us-male.mp3" data-audio-us-female="/audios/us/water-us-female.mp3"></span>.
-> * 喉塞音 <span class="pho">ʔ</span> - <span class="pho">m/n/l</span> 之前的 <span class="pho">t</span> 有可能变成喉塞音 <span class="pho">ʔ</span>，比如，*utmost* <span class="pho alt">ˈʌʔˌmoʊst</span><span class="speak-word-inline" data-audio-us-male="/audios/us/utmost-us-male.mp3" data-audio-us-female="/audios/us/utmost-us-female.mp3"></span>, *fitness* <span class="pho alt">ˈfɪʔnəs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/fitness-us-male.mp3" data-audio-us-female="/audios/us/fitness-us-female.mp3"></span>, *witness* <span class="pho alt">ˈwɪʔnəs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/witness-us-male.mp3" data-audio-us-female="/audios/us/witness-us-female.mp3"></span>, 或 *fruitless* <span class="pho alt">ˈfruːtləs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/fruitless-us-male.mp3" data-audio-us-female="/audios/us/fruitless-us-female.mp3"></span>。如果你不知道喉塞音是什么样的，听听 *Uh-Oh!* <span class="speak-word-inline" data-audio-us-female="/audios/us/Uh-Oh.mp3"></span>—— <span class="pho alt">ʌʔoʊ</span>……
-> * Glottal Stop <span class="pho">ʔ</span> - The <span class="pho">t</span> before <span class="pho">m/n/l</span> might transform into a glottal stop, as in *utmost* <span class="pho alt">ˈʌʔˌmoʊst</span><span class="speak-word-inline" data-audio-us-male="/audios/us/utmost-us-male.mp3" data-audio-us-female="/audios/us/utmost-us-female.mp3"></span>, *fitness* <span class="pho alt">ˈfɪʔnəs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/fitness-us-male.mp3" data-audio-us-female="/audios/us/fitness-us-female.mp3"></span>, *witness* <span class="pho alt">ˈwɪʔnəs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/witness-us-male.mp3" data-audio-us-female="/audios/us/witness-us-female.mp3"></span>, or *fruitless* <span class="pho alt">ˈfruːtləs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/fruitless-us-male.mp3" data-audio-us-female="/audios/us/fruitless-us-female.mp3"></span>. If you don't understand what is a *glottal stop*, listen to the phrase,  *Uh-Oh!* <span class="speak-word-inline" data-audio-us-female="/audios/us/Uh-Oh.mp3"></span>—— <span class="pho alt">ʌʔoʊ</span>...
-> * 省略音/可选音 <span class="pho">ᵗ</span> - 非重读音节末尾 <span class="pho">n</span> 之后的 <span class="pho">t</span> 可能会被省略掉，比如，*winter* <span class="pho alt">ˈwɪnᵗɚ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/winter-us-male.mp3" data-audio-us-female="/audios/us/winter-us-female.mp3"></span> —— 当然，若是读成 <span class="pho alt">ˈwɪntɚ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/winter-t-us-male.mp3" data-audio-us-female="/audios/us/winter-t-us-female.mp3"></span>也没错……[^1] 。
-> * Optional <span class="pho">ᵗ</span> - The <span class="pho">t</span> following <span class="pho">n</span> at the end of an unstressed syllable might be omitted, as in *winter* <span class="pho alt">ˈwɪnᵗɚ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/winter-us-male.mp3" data-audio-us-female="/audios/us/winter-us-female.mp3"></span> - of course, <span class="pho alt">ˈwɪntɚ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/winter-t-us-male.mp3" data-audio-us-female="/audios/us/winter-t-us-female.mp3"></span>is also correct.[^2]
-
-美式发音中，相对最特殊也需要最多注意和练习的辅音是 <span class="pho">t</span>，元音是 <span class="pho">ɚ/ɝː</span>（[2.1.5](2.1.5-ə)）。
-
-In American English pronunciation, the consonant <span class="pho">t</span> and the vowel sound <span class="pho">ɚ/ɝː</span> ([2.1.5](2.1.5-ə)) deserve special attention and practice due to their unique characteristics.
-
-[^1]: 非重读音节末尾的 *nd* 中的 <span class="pho">d</span> 也常常并不发音，最常见的比如 *and* 会被读作 <span class="pho alt">ən</span>，再比如，*a second offer* 会被说成 <span class="pho alt">ə ˈsekən‿ɑːfɚ</span>。甚至，<span class="pho">ntʃ</span> 也常常被读成 <span class="pho">nᵗʃ</span>，比如，*adventure* <span class="pho">/ədˈvenᵗʃɚ/</span>, 或者 *French* <span class="pho">/frenᵗʃ/</span> —— 在 <span class="pho">nᵗʃ</span> 这一点上，美式英语和英式英语都一样。
-
-[^2]: In American English, the <span class="pho">d</span> in "*nd*" at the end of an unstressed syllable also often goes silent. For example, "*and*" is usually pronounced as <span class="pho alt">ən</span>. Another instance is "*a second offer*," which sounds like <span class="pho alt">ə ˈsekən‿ɑːfɚ</span>. Even <span class="pho">ntʃ</span> is often pronounced as <span class="pho">nᵗʃ</span>. For example, adventure <span class="pho">/ədˈvenᵗʃɚ/</span> or French <span class="pho">/frenᵗʃ/</span>. In this respect, <span class="pho">nᵗʃ</span>, American English and British English are the same.
-
-## 拼写（Spellings）
-
-### <span class="pho">t</span>
-
-* **t**
-  * take <span class="pho alt">teɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/take-us-male.mp3" data-audio-us-female="/audios/us/take-us-female.mp3"></span>
-  * top <span class="pho alt">tɑːp</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/top-us-male.mp3" data-audio-us-female="/audios/us/top-us-female.mp3"></span>
-  * tilt <span class="pho alt">tɪlt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/tilt-us-male.mp3" data-audio-us-female="/audios/us/tilt-us-female.mp3"></span>
-* **th**
-  * Thomas <span class="pho alt">ˈtoʊm.əs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/thomas-us-male.mp3" data-audio-us-female="/audios/us/thomas-us-female.mp3"></span>
-  * Thames <span class="pho alt">temz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/thames-us-male.mp3" data-audio-us-female="/audios/us/thames-us-female.mp3"></span>
-  * thyme <span class="pho alt">taɪm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/thyme-us-male.mp3" data-audio-us-female="/audios/us/thyme-us-female.mp3"></span>
-* **tt**
-  * butter <span class="pho alt">ˈbʌt̬.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/butter-us-male.mp3" data-audio-us-female="/audios/us/butter-us-female.mp3"></span>
-  * little <span class="pho alt">ˈlɪt̬.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/little-us-male.mp3" data-audio-us-female="/audios/us/little-us-female.mp3"></span>
-  * matter <span class="pho alt">ˈmæt̬.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/matter-us-male.mp3" data-audio-us-female="/audios/us/matter-us-female.mp3"></span>
-* **ght**
-  * caught <span class="pho alt">kɑːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/caught-us-male.mp3" data-audio-us-female="/audios/us/caught-us-female.mp3"></span>
-  * taught <span class="pho alt">tɑːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/taught-us-male.mp3" data-audio-us-female="/audios/us/taught-us-female.mp3"></span>
-  * thought <span class="pho alt">θɑːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/thought-us-male.mp3" data-audio-us-female="/audios/us/thought-us-female.mp3"></span>
-* **ed** (after a voiceless consonant <span class="pho">p, k, f, s, sh, ch, th</span>)
-  * hoped <span class="pho alt">hoʊpt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/hoped-us-male.mp3" data-audio-us-female="/audios/us/hoped-us-female.mp3"></span>
-  * laughed <span class="pho alt">læft</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/laughed-us-male.mp3" data-audio-us-female="/audios/us/laughed-us-female.mp3"></span>
-  * liked <span class="pho alt">laɪkt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/liked-us-male.mp3" data-audio-us-female="/audios/us/liked-us-female.mp3"></span>
-  * watched <span class="pho alt">wɑːtʃt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/watched-us-male.mp3" data-audio-us-female="/audios/us/watched-us-female.mp3"></span>
-
-### <span class="pho">d</span>
-
-* **d**
-  * dog <span class="pho alt">dɑːɡ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/dog-us-male.mp3" data-audio-us-female="/audios/us/dog-us-female.mp3"></span>
-  * deed <span class="pho alt">diːd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/deed-us-male.mp3" data-audio-us-female="/audios/us/deed-us-female.mp3"></span>
-  * need <span class="pho alt">niːd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/need-us-male.mp3" data-audio-us-female="/audios/us/need-us-female.mp3"></span>
-* **dd**
-  * add <span class="pho alt">æd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/add-us-male.mp3" data-audio-us-female="/audios/us/add-us-female.mp3"></span>
-  * riddle <span class="pho alt">ˈrɪd.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/riddle-us-male.mp3" data-audio-us-female="/audios/us/riddle-us-female.mp3"></span>
-  * sudden <span class="pho alt">ˈsʌd.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sudden-us-male.mp3" data-audio-us-female="/audios/us/sudden-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.2.4-kg.md b/1000-hours/sounds-of-american-english-old/2.2.4-kg.md
deleted file mode 100644
index df4e2f68..00000000
--- a/1000-hours/sounds-of-american-english-old/2.2.4-kg.md
+++ /dev/null
@@ -1,59 +0,0 @@
-# 2.2.4 <span class="pho">k/g</span>
-
-幸亏各种语言里都有这两个音，否则的话，它们学起来原本可能挺困难……
-
-Thankfully, these two sounds exist in almost every language. Otherwise, learning them could prove quite challenging.
-
-首先，这两个音需要舌背后部抬起来顶住软腭而后开始发音。这个动作在口腔深处，所以无法直接看到。绝大多数人其实并不知道自己具体是怎么发出这两个声音的，也没有人能想起来自己小时候是如何学会的。
-
-Firstly, to pronounce these two sounds, the back part of the tongue must be raised and pressed against the *soft palate*. This action takes place deep in the mouth, so it's not something we can see directly. In fact, most people don't even know exactly how they produce these sounds, nor can anyone recall how they learned to make them as children.
-
-![articulator-tongue-tip-kg](/images/articulator-tongue-tip-kg.svg)
-
-就好像 <span class="pho">t/d</span> 在发音的时候一样，<span class="pho">k/g</span> 也会自然带着一个很轻的元音，再一次，不是 <span class="pho">ə</span> 而是 <span class="pho">ɤ</span><span class="speak-word-inline" data-audio-other="/audios/us/Close-mid_back_unrounded_vowel.ogg.mp3"></span>，但只有气流通过，没有声带振动。请仔细体会一下 *class* 的发音：<span class="pho alt">klæs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/class-us-male.mp3" data-audio-us-female="/audios/us/class-us-female.mp3"></span> —— 其中 <span class="pho">ɤ</span> 的音色，虽然轻微但也明显。
-
-Moreover, much like the <span class="pho">t/d</span> sounds, <span class="pho">k/g</span> also naturally carries a slight vowel sound. Once again, it's not <span class="pho">ə</span> but <span class="pho">ɤ</span><span class="speak-word-inline" data-audio-other="/audios/us/Close-mid_back_unrounded_vowel.ogg.mp3"></span>, where the air is flowing through without any vocal cord vibration. Pay close attention to the pronunciation of class: <span class="pho alt">klæs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/class-us-male.mp3" data-audio-us-female="/audios/us/class-us-female.mp3"></span>. The sound ɤ is subtle yet noticeable.
-
-另外，夹在两个元音之间的 <span class="pho">k</span> 也会出现像 <span class="pho">t</span> 夹在两个元音之间时那样的浊化现象，听起来更接近 
- <span class="pho">g</span>。比如，*look out*<span class="speak-word-inline" data-audio-us-male="/audios/us/lookout-us-male.mp3" data-audio-us-female="/audios/us/lookout-us-female.mp3"></span>，*seek out*<span class="speak-word-inline" data-audio-us-male="/audios/us/seekout-us-male.mp3" data-audio-us-female="/audios/us/seekout-us-female.mp3"></span>，*woke up*<span class="speak-word-inline" data-audio-us-male="/audios/us/wokeup-us-male.mp3" data-audio-us-female="/audios/us/wokeup-us-female.mp3"></span>。
-
- Also, when a <span class="pho">k</span> comes between two vowels, it can undergo a similar voicing change as a <span class="pho">t</span> between two vowels, making it sound closer to a <span class="pho">g</span>. For example, in *look out*<span class="speak-word-inline" data-audio-us-male="/audios/us/lookout-us-male.mp3" data-audio-us-female="/audios/us/lookout-us-female.mp3"></span> and *seek out*<span class="speak-word-inline" data-audio-us-male="/audios/us/seekout-us-male.mp3" data-audio-us-female="/audios/us/seekout-us-female.mp3"></span>, *woke up*<span class="speak-word-inline" data-audio-us-male="/audios/us/wokeup-us-male.mp3" data-audio-us-female="/audios/us/wokeup-us-female.mp3"></span>.
- 
-## 拼写（Spellings）
- 
-### <span class="pho">k</span>
-
-* **k**
-  * kid <span class="pho alt">kɪd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/kid-us-male.mp3" data-audio-us-female="/audios/us/kid-us-female.mp3"></span>
-  * like <span class="pho alt">laɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/like-us-male.mp3" data-audio-us-female="/audios/us/like-us-female.mp3"></span>
-  * skin <span class="pho alt">skɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/skin-us-male.mp3" data-audio-us-female="/audios/us/skin-us-female.mp3"></span>
-* **c**
-  * climb <span class="pho alt">klaɪm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/climb-us-male.mp3" data-audio-us-female="/audios/us/climb-us-female.mp3"></span>
-  * cream <span class="pho alt">kriːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/cream-us-male.mp3" data-audio-us-female="/audios/us/cream-us-female.mp3"></span>
-  * cry <span class="pho alt">kraɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/cry-us-male.mp3" data-audio-us-female="/audios/us/cry-us-female.mp3"></span>
-* **ch**
-  * ache <span class="pho alt">eɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/ache-us-male.mp3" data-audio-us-female="/audios/us/ache-us-female.mp3"></span>
-  * chemistry <span class="pho alt">ˈkem.ə.stri</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/chemistry-us-male.mp3" data-audio-us-female="/audios/us/chemistry-us-female.mp3"></span>
-  * school <span class="pho alt">skuːl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/school-us-male.mp3" data-audio-us-female="/audios/us/school-us-female.mp3"></span>
-* **ck**
-  * brick <span class="pho alt">brɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/brick-us-male.mp3" data-audio-us-female="/audios/us/brick-us-female.mp3"></span>
-  * click <span class="pho alt">klɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/click-us-male.mp3" data-audio-us-female="/audios/us/click-us-female.mp3"></span>
-  * kick <span class="pho alt">kɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/kick-us-male.mp3" data-audio-us-female="/audios/us/kick-us-female.mp3"></span>
-
-### <span class="pho">g</span>
-
-* **g**
-  * get <span class="pho alt">ɡet</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/get-us-male.mp3" data-audio-us-female="/audios/us/get-us-female.mp3"></span>
-  * go <span class="pho alt">ɡoʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/go-us-male.mp3" data-audio-us-female="/audios/us/go-us-female.mp3"></span>
-  * logo <span class="pho alt">ˈloʊɡoʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/logo-us-male.mp3" data-audio-us-female="/audios/us/logo-us-female.mp3"></span>
-* **gg**
-  * beggar<span class="pho alt">ˈbeɡ.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/beggar-us-male.mp3" data-audio-us-female="/audios/us/egg-us-female.mp3"></span>
-  * egg <span class="pho alt">eɡ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/egg-us-male.mp3" data-audio-us-female="/audios/us/egg-us-female.mp3"></span>
-  * waggle <span class="pho alt">ˈwæɡ.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/waggle-us-male.mp3" data-audio-us-female="/audios/us/waggle-us-female.mp3"></span>
-* **gh**
-  * ghost <span class="pho alt">ɡoʊst</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/ghost-us-male.mp3" data-audio-us-female="/audios/us/ghost-us-female.mp3"></span>
-  * ghetto <span class="pho alt">ˈɡet̬.oʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/ghetto-us-male.mp3" data-audio-us-female="/audios/us/ghetto-us-female.mp3"></span>
-* **gu**
-  * guard <span class="pho alt">ɡɑːrd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/guard-us-male.mp3" data-audio-us-female="/audios/us/guard-us-female.mp3"></span>
-  * guide <span class="pho alt">ɡaɪd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/guide-us-male.mp3" data-audio-us-female="/audios/us/guide-us-female.mp3"></span>
-  * guitar <span class="pho alt">ɡɪˈtɑːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/guitar-us-male.mp3" data-audio-us-female="/audios/us/guitar-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.2.5-fv.md b/1000-hours/sounds-of-american-english-old/2.2.5-fv.md
deleted file mode 100644
index e55c550f..00000000
--- a/1000-hours/sounds-of-american-english-old/2.2.5-fv.md
+++ /dev/null
@@ -1,42 +0,0 @@
-# 2.2.5 <span class="pho">f/v</span>
-
-与 <span class="pho">k/g</span> 不一样，<span class="pho">f/v</span> 的发声重点是可以看到的：下嘴唇略微收回，上牙贴在下嘴唇上，而后开始发音。
-
-Unlike <span class="pho">k/g</span>, the articulation of <span class="pho">f/v</span> is actually visible: the *lower lip* retracts slightly, and the *upper teeth* rest on the lower lip before beginning to sound.
-
-![articulator-tongue-tip-fv](/images/articulator-tongue-tip-fv.svg)
-
-韩语中没有这两个音，所以，他们会不由自主地用 <span class="pho">p</span> 替代 <span class="pho">f</span>，用 <span class="pho">b</span> 替代 <span class="pho">v</span>；所以，我们经常会听到韩国人把 *photo* 说成 <span class="pho alt">ˈpoʊˌtoʊ</span><span class="speak-word-inline" data-audio-other="/audios/us/photo-ko-kr.mp3"></span>，把 *video* 说成 <span class="pho alt">ˈbɪdioʊ</span><span class="speak-word-inline" data-audio-other="/audios/us/video-ko-kr.mp3"></span>……
-
-The Korean language lacks these two sounds, so Koreans will instinctively replace <span class="pho">f</span> with <span class="pho">p</span> and <span class="pho">v</span> with <span class="pho">b</span>. As a result, you often hear Koreans pronouncing *video* as <span class="pho alt">ˈpoʊˌtoʊ</span><span class="speak-word-inline" data-audio-other="/audios/us/photo-ko-kr.mp3"></span> and *video* as <span class="pho alt">ˈbɪdioʊ</span><span class="speak-word-inline" data-audio-other="/audios/us/video-ko-kr.mp3"></span>...
-
-中国南方有些方言里也没有 <span class="pho">f</span>，所以，他们可能会用 <span class="pho">hw</span> 替代 <span class="pho">f</span>，比如，把 *fight* 读成 <span class="pho alt">hwaɪt</span>；中文的普通话里没有 <span class="pho">v</span>，所以，中国人经常把用 <span class="pho">w</span> 替换 <span class="pho">v</span>，比如，把 *very* 读成 <span class="pho alt">ˈwɛri</span><span class="speak-word-inline" data-audio-other="/audios/us/very-cn-zh.mp3"></span>……
-
-Some dialects in southern China also lack the <span class="pho">f</span> sound, so speakers might substitute <span class="pho">f</span> with <span class="pho">hw</span>. For instance, they might pronounce <span class="pho">fight</span> as <span class="pho alt">hwaɪt</span>. Mandarin Chinese doesn't have a <span class="pho">v</span> sound, so Chinese speakers often replace <span class="pho">v</span> with <span class="pho">w</span>, like pronouncing <span class="pho">very</span> as <span class="pho alt">ˈwɛri</span><span class="speak-word-inline" data-audio-other="/audios/us/very-cn-zh.mp3"></span>...
-
-另外需要注意的是，与 <span class="pho">p/b</span>、<span class="pho">t/d</span>、<span class="pho">k/g</span> 不一样，<span class="pho">f/v</span> 在发声的时候**不带**任何轻微的元音音色。
-
-Another thing to note is that, unlike <span class="pho">p/b</span>, <span class="pho">t/d</span>, and <span class="pho">k/g</span>, <span class="pho">f/v</span> are pronounced *without* any slight vowel qualities.
-
-## 拼写（Spellings）
-
-### <span class="pho">f</span>
-
-* **f**
-  * fight <span class="pho alt">faɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/fight-us-male.mp3" data-audio-us-female="/audios/us/fight-us-female.mp3"></span>
-  * life <span class="pho alt">laɪf</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/life-us-male.mp3" data-audio-us-female="/audios/us/life-us-female.mp3"></span>
-  * wife <span class="pho alt">waɪf</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/wife-us-male.mp3" data-audio-us-female="/audios/us/wife-us-female.mp3"></span>
-* **ph**
-  * photo <span class="pho alt">ˈfoʊ.t̬oʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/photo-us-male.mp3" data-audio-us-female="/audios/us/photo-us-female.mp3"></span>
-  * coffee <span class="pho alt">ˈkɑː.fi</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/coffee-us-male.mp3" data-audio-us-female="/audios/us/coffee-us-female.mp3"></span>
-  * elephant <span class="pho alt">ˈel.ə.fənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/elephant-us-male.mp3" data-audio-us-female="/audios/us/elephant-us-female.mp3"></span>
-
-### <span class="pho">v</span>
-
-* **v**
-  * live <span class="pho alt">lɪv</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/live-us-male.mp3" data-audio-us-female="/audios/us/live-us-female.mp3"></span>
-  * vector <span class="pho alt">ˈvek.tɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/vector-us-male.mp3" data-audio-us-female="/audios/us/vector-us-female.mp3"></span>
-  * vine <span class="pho alt">vaɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/vine-us-male.mp3" data-audio-us-female="/audios/us/vine-us-female.mp3"></span>
-* **vv**
-  * chivvy <span class="pho alt">ˈtʃɪv.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/chivvy-us-male.mp3" data-audio-us-female="/audios/us/chivvy-us-female.mp3"></span>
-  * divvy <span class="pho alt">ˈdɪv.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/divvy-us-male.mp3" data-audio-us-female="/audios/us/divvy-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.2.6-sz.md b/1000-hours/sounds-of-american-english-old/2.2.6-sz.md
deleted file mode 100644
index 62cbbb81..00000000
--- a/1000-hours/sounds-of-american-english-old/2.2.6-sz.md
+++ /dev/null
@@ -1,63 +0,0 @@
-# 2.2.6. <span class="pho">s/z</span>
-
-<span class="pho">s/z</span> 对所有人来说都没有什么具体的难度。<span class="pho">s/z</span> 发声时起始的舌尖位置贴近但没有接触到牙齿和牙龈的接缝处 —— 即，位置 ②（参见 [1.4](1.4-articulators)）。
-
-The <span class="pho">s/z</span> sounds don't really pose a challenge for most people. When producing these sounds, the tip of the tongue is close to, but not touching, the *seam* between teeth and gums, i.e. position ② (as described in [1.4](1.4-articulators)).
-
-![articulator-tongue-tip-sz](/images/articulator-tongue-tip-sz.svg)
-
-中文里当然也有 <span class="pho">s</span> 这个音，但，中文里的 <span class="pho">s</span> 在发音时舌尖起始位置更接近下排牙齿，即，比位置 ② 更低一些 —— 虽然听不出什么区别。你可以再试着用中文普通话说一遍 “我踢死你！”（<span class="pho">wǒ tī sǐ nǐ</span>）<span class="speak-word-inline" data-audio-other="/audios/us/我踢死你-zh-cn-male.mp3"></span>…… 不过，作为中国人你需要新练一个 <span class="pho">s</span>，否则，说英文时经常遇到更费力的情况，比如，在说 <span class="pho">st</span> 这个组合的时候 —— 这恰好也是英文中使用频率相当高的一个组合。
-
-Of course, the sound <span class="pho">s</span> exists in Chinese as well, but when you pronounce it, the tip of your tongue starts closer to the lower teeth—slightly lower than position ②, even though you can't really hear the difference. Again, you can try this out by saying "wǒ tī sǐ nǐ" (我踢死你！)<span class="speak-word-inline" data-audio-other="/audios/us/我踢死你-zh-cn-male.mp3"></span> in Mandarin.However, for Chinese speakers, it's necessary to practice a new <span class="pho">s</span> sound to make speaking English less strenuous, especially when saying combinations like <span class="pho">st</span> — which happens to be a very common combination in English.
-
-另外，需要注意的是，<span class="pho">s</span> 之后的 <span class="pho">p/t/tr/k</span> 作为音节开头时会被浊化（比如，音节末尾的 <span class="pho">st</span> 中的 <span class="pho">t</span> 不会被浊化），相应读成 <span class="pho">b/d/dr/g</span>（但是，音标标注却保持原样）：
-
-Also, it's important to note that, following an <span class="pho">s</span> that starts a syllable, <span class="pho">p/t/tr/k</span> are voiced, meaning they are pronounced like <span class="pho">b/d/dr/g</span> respectively, while the phonetic annotations remain unchanged. However, this rule doesn't apply when these consonants are at the end of a syllable, like the <span class="pho">t</span> in <span class="pho">st</span>:
-
-> * *speak* <span class="pho alt">spiːk</span> → <span class="pho alt">sbiːk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/speak-us-male.mp3" data-audio-us-female="/audios/us/speak-us-female.mp3"></span>
-> * *student* <span class="pho alt">ˈstudənt</span> → <span class="pho alt">ˈsdudənt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/student-us-male.mp3" data-audio-us-female="/audios/us/student-us-female.mp3"></span>
-> * *school* <span class="pho alt">skuːl</span> → <span class="pho alt">sguːl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/school-us-male.mp3" data-audio-us-female="/audios/us/school-us-female.mp3"></span>
-> * *frustrate* <span class="pho alt">ˈfrʌˌstreɪt</span> → <span class="pho alt">ˈfrʌˌsdreɪt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/frustrate-us-male.mp3" data-audio-us-female="/audios/us/frustrate-us-female.mp3"></span>
-
-另外，英文的辅音并没有长短区分 —— 有些语言的辅音是有长短区分的，虽然亚洲语言基本都没有这种差别。然而，英文的 <span class="pho">f/v</span>、<span class="pho">s/z</span>、<span class="pho">ʃ</span> 以及 <span class="pho">ts</span> 是可以拉长的，尤其是 <span class="pho">s</span> 和 <span class="pho">ts</span>。
-
-In addition, in English, there's no differentiation between long and short consonant sounds. This is a feature found in some languages but is generally not present in Asian languages. However, in English, the sounds of <span class="pho">f/v</span>, <span class="pho">s/z</span>, <span class="pho">ʃ</span>, and <span class="pho">ts</span> can be lengthened, especially <span class="pho">s</span> and <span class="pho">ts</span>.
-
-## 拼写（Spellings）
-
-### <span class="pho">s</span>
-
-* **c**
-  * ceiling <span class="pho alt">ˈsiː.lɪŋ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/ceiling-us-male.mp3" data-audio-us-female="/audios/us/ceiling-us-female.mp3"></span>
-  * cedar <span class="pho alt">ˈsiː.dɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/cedar-us-male.mp3" data-audio-us-female="/audios/us/cedar-us-female.mp3"></span>
-  * concede <span class="pho alt">kənˈsiːd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/concede-us-male.mp3" data-audio-us-female="/audios/us/concede-us-female.mp3"></span>
-* **s**
-  * see <span class="pho alt">siː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/see-us-male.mp3" data-audio-us-female="/audios/us/see-us-female.mp3"></span>
-  * sea <span class="pho alt">siː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sea-us-male.mp3" data-audio-us-female="/audios/us/sea-us-female.mp3"></span>
-  * sick <span class="pho alt">sɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sick-us-male.mp3" data-audio-us-female="/audios/us/sick-us-female.mp3"></span>
-* **ss**
-  * boss <span class="pho alt">bɑːs</span> <span class="speak-word-inline"  data-audio-us-male="/audios/us/boss-us-male.mp3" data-audio-us-female="/audios/us/boss-us-female.mp3"></span>
-  * class <span class="pho alt">klæs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/class-us-male.mp3" data-audio-us-female="/audios/us/class-us-female.mp3"></span>
-  * stress <span class="pho alt">stres</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/stress-us-male.mp3" data-audio-us-female="/audios/us/stress-us-female.mp3"></span>
-* **sc**
-  * scene <span class="pho alt">siːn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/scene-us-male.mp3" data-audio-us-female="/audios/us/scene-us-female.mp3"></span>
-  * science <span class="pho alt">ˈsaɪ.əns</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/science-us-male.mp3" data-audio-us-female="/audios/us/science-us-female.mp3"></span>
-  * sceptic <span class="pho alt">ˈskep.tɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sceptic-us-male.mp3" data-audio-us-female="/audios/us/sceptic-us-female.mp3"></span>
-
-### <span class="pho">z</span>
-
-* **z**
-  * zone <span class="pho alt">zoʊn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/zone-us-male.mp3" data-audio-us-female="/audios/us/zone-us-female.mp3"></span>
-  * zebra <span class="pho alt">ˈziː.brə</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/zebra-us-male.mp3" data-audio-us-female="/audios/us/zebra-us-female.mp3"></span>
-* **zz**
-  * buzz <span class="pho alt">bʌz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/buzz-us-male.mp3" data-audio-us-female="/audios/us/buzz-us-female.mp3"></span>
-  * jazz <span class="pho alt">dʒæz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/jazz-us-male.mp3" data-audio-us-female="/audios/us/jazz-us-female.mp3"></span>
-  * puzzle <span class="pho alt">ˈpʌz.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/puzzle-us-male.mp3" data-audio-us-female="/audios/us/puzzle-us-female.mp3"></span>
-* **s**
-  * present <span class="pho alt">ˈprez.ənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/present-us-male.mp3" data-audio-us-female="/audios/us/present-us-female.mp3"></span>
-  * raise <span class="pho alt">reɪz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/raise-us-male.mp3" data-audio-us-female="/audios/us/raise-us-female.mp3"></span>
-  * rose <span class="pho alt">roʊz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/rose-us-male.mp3" data-audio-us-female="/audios/us/rose-us-female.mp3"></span>
-* **s** (forming plurals after vowels or voiced consonants)
-  * cars <span class="pho alt">kɑːrz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/cars-us-male.mp3" data-audio-us-female="/audios/us/cars-us-female.mp3"></span>
-  * trees <span class="pho alt">ˈtriːz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/trees-us-male.mp3" data-audio-us-female="/audios/us/trees-us-female.mp3"></span>
-  * brains <span class="pho alt">breɪnz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/brains-us-male.mp3" data-audio-us-female="/audios/us/brains-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.2.7-θð.md b/1000-hours/sounds-of-american-english-old/2.2.7-θð.md
deleted file mode 100644
index 7ec9b383..00000000
--- a/1000-hours/sounds-of-american-english-old/2.2.7-θð.md
+++ /dev/null
@@ -1,41 +0,0 @@
-# 2.2.7 <span class="pho">θ/ð</span>
-
-对很多人来说，<span class="pho">θ/ð</span> 相对较难 —— 主要是因为很多语言中没有这两个音，比如，中日韩都一样，都没有这两个音。
-
-For many people, producing the sounds <span class="pho">θ/ð</span> can be a challenge. This is primarily because these sounds aren't present in many languages. For instance, Chinese, Japanese, and Korean are all languages that don't have these sounds.
-
-![articulator-tongue-tip-th](/images/articulator-tongue-tip-th.svg)
-
-虽然，英语老师们都强调说，发这两个音的时候要用牙齿咬住一点点舌尖再发声，也就是说，舌尖要伸出牙齿一点点 —— 这么做当然发声更为清楚，在读单个音节或词汇的时候尤为明显……
-
-English teachers often emphasize that to produce these sounds, you should lightly bite the tip of your tongue with your teeth before vocalizing it - meaning, the tip of your tongue should slightly stick out past your teeth. Utilizing this technique undoubtedly makes your pronunciation clearer, especially when articulating individual syllables or words.
-
-但是，在连贯的自然语音之中，会有大量处于**非重音**位置的 <span class="pho">θ/ð</span> 发声时起始的舌尖位置并没有伸到牙齿之外，只是**贴在牙齿**上而已 —— 即，位置 ①（参见 [1.4](1.4-articulators)）。反过来，即便是处于**重音**位置的 <span class="pho">θ/ð</span>, 也一样可以把发声动作**简化**一下，只要舌尖贴到牙齿上，而后开始发音即可。
-
-However, within the flow of natural speech, many instances of the <span class="pho">θ/ð</span> that are in non-stressed positions start with the tongue tip not extending beyond the teeth, but only resting against them— that is, position ① (as described in [1.4](1.4-articulators)). Even when <span class="pho">θ/ð</span> phonemes are in stressed positions, the articulation can be simplified. All you need to do is place the tip of the tongue against the teeth, and then begin to vocalize.
-
-最初练习的时候，可以借助 <span class="pho">s/z</span> 作为辅助:
-
-> * 先发 <span class="pho">s</span> 的音，而后，把舌尖往前推一点点就接触到了牙齿，然后以与 <span class="pho">s</span> 同样的方式发音，就能听到 <span class="pho">θ</span>；然后分别说两个词 *sink* <span class="pho alt">sɪŋk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/sink-us-male.mp3" data-audio-us-female="/audios/us/sink-us-female.mp3"></span> 和 *think* <span class="pho alt">θɪŋk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/think-us-male.mp3" data-audio-us-female="/audios/us/think-us-female.mp3"></span>……
-> * 先发 <span class="pho">z</span> 的音，而后，把舌尖往前推一点点就接触到了牙齿，然后以与 <span class="pho">z</span> 同样的方式发音，就能听到 <span class="pho">ð</span>；然后分别说两个词 *zed* <span class="pho alt">zed</span><span class="speak-word-inline" data-audio-us-male="/audios/us/zed-us-male.mp3" data-audio-us-female="/audios/us/zed-us-female.mp3"></span> 和 *that* <span class="pho alt">ðæt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/that-us-male.mp3" data-audio-us-female="/audios/us/that-us-female.mp3"></span>……
-
-When you first start practicing, you can use the sounds of <span class="pho">s/z</span> as guides to help:
-
->* Begin by making the <span class="pho">s</span> sound. Then, gently push the tip of your tongue forward until it touches your teeth. After this, produce the sound in the same way as <span class="pho">s</span>, and you should hear the <span class="pho">θ</span>. Practice this with words like *sink* <span class="pho alt">sɪŋk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/sink-us-male.mp3" data-audio-us-female="/audios/us/sink-us-female.mp3"></span> and *think* <span class="pho alt">θɪŋk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/think-us-male.mp3" data-audio-us-female="/audios/us/think-us-female.mp3"></span>...
->* Start with the <span class="pho">z</span> sound. Again, push the tip of your tongue forward until it contacts your teeth. Create the sound as you would with <span class="pho">z</span>, and you should notice the <span class="pho">ð</span>. Try this with words such as *zed* <span class="pho alt">zed</span><span class="speak-word-inline" data-audio-us-male="/audios/us/zed-us-male.mp3" data-audio-us-female="/audios/us/zed-us-female.mp3"></span> and *that* <span class="pho alt">ðæt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/that-us-male.mp3" data-audio-us-female="/audios/us/that-us-female.mp3"></span>...
-
-## 拼写（Spellings）
-
-### <span class="pho">θ</span>
-
-* **th**
-  * think <span class="pho alt">θɪŋk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/think-us-male.mp3" data-audio-us-female="/audios/us/think-us-female.mp3"></span>
-  * bath <span class="pho alt">bæθ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bath-us-male.mp3" data-audio-us-female="/audios/us/bath-us-female.mp3"></span>
-  * wealth <span class="pho alt">welθ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/wealth-us-male.mp3" data-audio-us-female="/audios/us/wealth-us-female.mp3"></span>
-
-### <span class="pho">ð</span>
-
-* **th**
-  * this <span class="pho alt">ðɪs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/this-us-male.mp3" data-audio-us-female="/audios/us/this-us-female.mp3"></span>
-  * then <span class="pho alt">ðen</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/then-us-male.mp3" data-audio-us-female="/audios/us/then-us-female.mp3"></span>
-  * with <span class="pho alt">wɪð</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/with-us-male.mp3" data-audio-us-female="/audios/us/with-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.2.8-ʃʒ.md b/1000-hours/sounds-of-american-english-old/2.2.8-ʃʒ.md
deleted file mode 100644
index dcd5801d..00000000
--- a/1000-hours/sounds-of-american-english-old/2.2.8-ʃʒ.md
+++ /dev/null
@@ -1,68 +0,0 @@
-# 2.2.8. <span class="pho">ʃ/ʒ</span>
-
-<span class="pho">ʃ</span> 对很多人来说也许难度并不大，然而，<span class="pho">ʒ</span> 却可能非常难。再一次，关键在于发声时舌尖的起始位置 —— 即，位置 ③（参见 [1.4](1.4-articulators)）
-
-The pronunciation of <span class="pho">ʃ</span> may not pose much of a challenge for many people, yet <span class="pho">ʒ</span> can be extremely tough. Once again, the key lies in the initial position of the tongue tip when making the sound, i.e. position ③ (as described in [1.4](1.4-articulators)).
-
-![articulator-tongue-tip-sh](/images/articulator-tongue-tip-sh.svg)
-
-比较一下以下的辅音：
-
-Let's compare following consonants:
-
-> * <span class="pho">t/d</span> 的舌尖起始位置时贴在龈脊的前部 ③；
-> * For <span class="pho">t/d</span>, the tongue tip begins at the front part of *alveolar ridge* ③;
-> * <span class="pho">s/z</span> 要相对于 <span class="pho">t/d</span> 往前一些，贴近但没有接触到牙齿和牙龈的接缝处 ②；
-> * For <span class="pho">s/z</span>, it's closer to the front compared to <span class="pho">t/d</span>, near but not touching the *seam* between the teeth and gums ②;
-> * <span class="pho">θ/ð</span> 要相对于 <span class="pho">s/z</span>再往前一些，贴在牙齿上，或者伸出牙齿一点点 ①；
-> * For <span class="pho">θ/ð</span>, it's even more forward than <span class="pho">s/z</span>, resting on the *teeth*, or protruding a bit ①;
-> * <span class="pho">ʃ/ʒ</span> 和 <span class="pho">t/d</span> 一样，贴近但没有接触到龈脊的那个部位 ③；
-> * For <span class="pho">ʃ/ʒ</span>, it's almost same as <span class="pho">t/d</span>, near but not touching the part of the *alveolar ridge* ③;
-> * <span class="pho">r</span> 相对于 <span class="pho">ʃ/ʒ</span> 还要再往后一点，贴在龈脊的那个部位 ④……
-> * For <span class="pho">r</span>, it's further back than <span class="pho">ʃ/ʒ</span>, touching the part of the *alveolar ridge* ④...
-
-![articulator-tongue-tip-positions](/images/articulator-tongue-tip-positions.svg)
-
-除了英语之外，大多语言里没有 <span class="pho">ʒ</span> 这个辅音。即便是在英语里，含有这个辅音的词汇也很少，常见的不过几十个而已。
-
-Apart from English, most languages do not have the <span class="pho">ʒ</span> consonant. Even in English, there are only a handful of words that contain this sound.
-
-中国学生会不由自主地用 <span class="pho">dʒ</span> 替代 <span class="pho">ʒ</span> —— 因为 <span class="pho">dʒ</span> 是一个他们熟悉的辅音，相当于中文拼音中的 <span class="pho">zh</span>。<span class="pho">ʒ</span> 和 <span class="pho">dʒ</span> 的区别在于，<span class="pho">ʒ</span> 发声时舌尖贴近但没有接触到龈脊；而 <span class="pho">dʒ</span> 发声时起始的舌尖贴在龈脊（与 <span class="pho">ʒ</span> 同一个位置 ③）。
-
-Chinese students tend to instinctively substitute <span class="pho">ʒ</span> with <span class="pho">dʒ</span> - a consonant they're familiar with, equivalent to the <span class="pho">zh</span> in Chinese Pinyin. The difference between <span class="pho">ʒ</span> and <span class="pho">dʒ</span> is that, when pronouncing <span class="pho">ʒ</span>, the tip of the tongue is close to but not touching the the *alveolar ridge* while for <span class="pho">dʒ</span>, the tongue tip starts at the the *alveolar ridge* (same position as <span class="pho">ʒ</span> ③).
-
-少数人知道  <span class="pho">dʒ</span> 替代 <span class="pho">ʒ</span> 不是一回事，但，由于舌尖起始位置并不准确，所以他们说出来的 <span class="pho">ʒ</span> 听起来更接近 <span class="pho">r</span> —— 舌尖缩得过头了 —— <span class="pho">r</span> ④ 发声时起始的舌尖位置相对于 <span class="pho">ʒ</span> ③ 要更靠后一点。
-
-A few understand that substituting <span class="pho">dʒ</span> for <span class="pho">ʒ</span> isn't accurate. However, because their tongue tip positioning isn't precise, their <span class="pho">ʒ</span> sound often ends up sounding more like <span class="pho">r</span> - they retract their tongue tip too far - <span class="pho">r</span> ④ is pronounced with the tongue tip further back compared to <span class="pho">ʒ</span> ③ .
-
-## 拼写（Spellings）
-
-### <span class="pho">ʃ</span>
-
-* **s**
-  * sugar <span class="pho alt">ˈʃʊɡ.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sugar-us-male.mp3" data-audio-us-female="/audios/us/sugar-us-female.mp3"></span>
-  * sure <span class="pho alt">ʃʊr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sure-us-male.mp3" data-audio-us-female="/audios/us/sure-us-female.mp3"></span>
-* **ch**
-  * chef <span class="pho alt">ʃef</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/chef-us-male.mp3" data-audio-us-female="/audios/us/chef-us-female.mp3"></span>
-  * machine <span class="pho alt">məˈʃiːn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/machine-us-male.mp3" data-audio-us-female="/audios/us/machine-us-female.mp3"></span>
-* **sh**
-  * finish <span class="pho alt">ˈfɪn.ɪʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/finish-us-male.mp3" data-audio-us-female="/audios/us/finish-us-female.mp3"></span>
-  * sheep <span class="pho alt">ʃiːp</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sheep-us-male.mp3" data-audio-us-female="/audios/us/sheep-us-female.mp3"></span>
-* **ss**
-  * discussion <span class="pho alt">dɪˈskʌʃ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/discussion-us-male.mp3" data-audio-us-female="/audios/us/discussion-us-female.mp3"></span>
-  * mission <span class="pho alt">ˈmɪʃ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/mission-us-male.mp3" data-audio-us-female="/audios/us/mission-us-female.mp3"></span>
-  * pressure <span class="pho alt">ˈpreʃ.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pressure-us-male.mp3" data-audio-us-female="/audios/us/pressure-us-female.mp3"></span>
-
-### <span class="pho">ʒ</span>
-
-* **g**
-  * genre <span class="pho alt">ˈʒɑːn.rə</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/genre-us-male.mp3" data-audio-us-female="/audios/us/genre-us-female.mp3"></span>
-  * garage <span class="pho alt">ɡəˈrɑːʒ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/garage-us-male.mp3" data-audio-us-female="/audios/us/garage-us-female.mp3"></span>
-* **s**
-  * measure <span class="pho alt">ˈmeʒ.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/measure-us-male.mp3" data-audio-us-female="/audios/us/measure-us-female.mp3"></span>
-  * leisure <span class="pho alt">ˈliː.ʒɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/leisure-us-male.mp3" data-audio-us-female="/audios/us/leisure-us-female.mp3"></span>
-  * decision <span class="pho alt">dɪˈsɪʒ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/decision-us-male.mp3" data-audio-us-female="/audios/us/decision-us-female.mp3"></span>
-  * fusion <span class="pho alt">ˈfjuː.ʒən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/fusion-us-male.mp3" data-audio-us-female="/audios/us/fusion-us-female.mp3"></span>
-* **z**
-  * azure <span class="pho alt">ˈæʒ.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/azure-us-male.mp3" data-audio-us-female="/audios/us/azure-us-female.mp3"></span>
-
diff --git a/1000-hours/sounds-of-american-english-old/2.2.9-h.md b/1000-hours/sounds-of-american-english-old/2.2.9-h.md
deleted file mode 100644
index 05df8639..00000000
--- a/1000-hours/sounds-of-american-english-old/2.2.9-h.md
+++ /dev/null
@@ -1,28 +0,0 @@
-# 2.2.9. <span class="pho">h</span>
-
-不管人们用什么样的语言，笑声总是一致的…… 因为地球人在发笑的时候都使用大致一样的声音，都包含 <span class="pho">h</span> 这个音 —— 于是，没有人会觉得 <span class="pho">h</span> 的发音有什么困难。
-
-No matter what language people speak, laughter sounds the same... That's because people all over the world use roughly the same sound when they laugh, one that includes the <span class="pho">h</span> sound. As a result, no one finds it difficult to pronounce <span class="pho">h</span>.
-
-不过有一个细节需要注意。在日常对话中，不能么正式或者速度较快的时候，<span class="pho">h</span> 会被 “击穿”。比如，*Did he do that?* 这句话，更可能被说成 <span class="pho alt">dɪ diː duː ðæt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-he-do-alloy.mp3" data-audio-us-female="/audios/us/sentence-he-do-nova.mp3"></span>，而不是正式的那样 <span class="pho alt">dɪd hiː duː ðæt</span>。
-
-However, there's one detail to keep in mind. In everyday conversations, especially when speaking informally or quickly, the <span class="pho">h</span> sound can get "dropped." For example, the sentence *Did he do that?* is more likely to be pronounced as <span class="pho alt">dɪ diː duː ðæt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-he-do-alloy.mp3" data-audio-us-female="/audios/us/sentence-he-do-nova.mp3"></span> rather than the formal one as <span class="pho alt">dɪd hiː duː ðæt</span>.
-
-更多的例子比如：
-
-For more examples:
-
-* I heard him singing. <span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-heard-him-alloy.mp3" data-audio-us-female="/audios/us/sentence-heard-him-nova.mp3"></span>
-* Has he arrived yet? <span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-he-arrived-alloy.mp3" data-audio-us-female="/audios/us/sentence-he-arrived-nova.mp3"></span>
-* He helped her with the project. <span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-helped-her-alloy.mp3" data-audio-us-female="/audios/us/sentence-helped-her-nova.mp3"></span>
-* His house is over there. <span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-house-is-alloy.mp3" data-audio-us-female="/audios/us/sentence-house-is-nova.mp3"></span>
-* He's holding the door. <span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-holding-the-alloy.mp3" data-audio-us-female="/audios/us/sentence-holding-the-nova.mp3"></span>
-
-## 拼写（Spellings）
-
-### <span class="pho">h</span>
-
-* **h**
-  * hello <span class="pho alt">heˈloʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/hello-us-male.mp3" data-audio-us-female="/audios/us/hello-us-female.mp3"></span>
-  * heat <span class="pho alt">hiːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/heat-us-male.mp3" data-audio-us-female="/audios/us/heat-us-female.mp3"></span>
-  * high <span class="pho alt">haɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/high-us-male.mp3" data-audio-us-female="/audios/us/high-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.3-syllables.md b/1000-hours/sounds-of-american-english-old/2.3-syllables.md
deleted file mode 100644
index ce6eed5b..00000000
--- a/1000-hours/sounds-of-american-english-old/2.3-syllables.md
+++ /dev/null
@@ -1,16 +0,0 @@
-# 音节
-
-这是所有语言共同的特性：
-
-Here are some universal features of all languages around the world:
-
-> * 自然语音都以**音节**为最基础单位。
-> * The basic unit of all natural speech is the **syllable**.
-> * 音节以**元音**为核心。
-> * Every syllable is centered around a **vowel**.
-> * 每个音节**有且只有一个**元音。
-> * Each syllable **has and only has one** vowel.
-
-元音之于音节，正如细胞核之于细胞。
-
-A *vowel* is to a syllyble, just as a *nucleus* to a cell.
diff --git a/1000-hours/sounds-of-american-english-old/2.3.1-structure.md b/1000-hours/sounds-of-american-english-old/2.3.1-structure.md
deleted file mode 100644
index 17738b03..00000000
--- a/1000-hours/sounds-of-american-english-old/2.3.1-structure.md
+++ /dev/null
@@ -1,32 +0,0 @@
-# 2.3.1. 构成（Structure of a syllable）
-
-**英文的词汇由至少一个音节构成**。英文中出现频率最高的几个词，*a/an*, *the*, *of*, *to*, *for*... 等等都是单音节词汇。有的词汇可能很长，由很多音节构成。在英文词典中能找到的最长词汇总计由 19 个音节，45 个字母构成：
-
-> *[Pneumonoultramicroscopicsilicovolcanoconiosis](https://en.wikipedia.org/wiki/Pneumonoultramicroscopicsilicovolcanoconiosis)* <span class="speak-word-inline" data-audio-us-female="/audios/En-us-pneumonoultramicroscopicsilicovolcanoconiosis.ogg.mp3"></span>
->
-> <span class="pho alt">ˌnumənəʊˌəltrəˌmaɪkrəˌskɑpɪkˌsɪləkəʊvɑlˌkeɪnəʊˌkəʊniˈəʊsəs</span>
-
-一个音节中，有且只有一个元音（被称为  *nucleus*），也是该音节的韵（*rhyme*）。音节以元音为核心，前后可有多达三个辅音构成的组合。
-
-In a syllable, there is *only* one vowel, known as the *nucleus*, which forms the *rhyme* of the syllable. This vowel is at the core of the syllable, and it can be surrounded by up to three consonants.
-
-英文的音节构成大抵上有以下几种形式（其中，<span class="pho">c</span> 代表辅音，<span class="pho">v</span> 代表元音）：
-
-In English, syllables can generally be made up of the following patterns (where <span class="pho">c</span> stands for consonant and <span class="pho">v</span> stands for vowel):
-
-> * <span class="pho">v</span> - *awe* <span class="pho alt">ɑː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/awe-us-male.mp3" data-audio-us-female="/audios/us/awe-us-female.mp3"></span>
-> * <span class="pho">vc</span> - *add* <span class="pho alt">æd</span><span class="speak-word-inline" data-audio-us-male="/audios/us/add-us-male.mp3" data-audio-us-female="/audios/us/add-us-female.mp3"></span>
-> * <span class="pho">vcc</span> - *east* <span class="pho alt">iːst</span><span class="speak-word-inline" data-audio-us-male="/audios/us/east-us-male.mp3" data-audio-us-female="/audios/us/east-us-female.mp3"></span>
-> * <span class="pho">vccc</span> - *axed* <span class="pho alt">ækst</span><span class="speak-word-inline" data-audio-us-male="/audios/us/axed-us-male.mp3" data-audio-us-female="/audios/us/axed-us-female.mp3"></span>
-> * <span class="pho">cv</span> - *the* <span class="pho alt">ðə</span><span class="speak-word-inline" data-audio-us-male="/audios/us/the-us-male.mp3" data-audio-us-female="/audios/us/the-us-female.mp3"></span>
-> * <span class="pho">cvc</span> - *dog* <span class="pho alt">dɑːɡ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/dog-us-male.mp3" data-audio-us-female="/audios/us/dog-us-female.mp3"></span>
-> * <span class="pho">cvcc</span> - *task* <span class="pho alt">tæsk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/task-us-male.mp3" data-audio-us-female="/audios/us/task-us-female.mp3"></span>
-> * <span class="pho">cvccc</span> - *text* <span class="pho alt">tekst</span><span class="speak-word-inline" data-audio-us-male="/audios/us/text-us-male.mp3" data-audio-us-female="/audios/us/text-us-female.mp3"></span>
-> * <span class="pho">ccv</span> - *flee* <span class="pho alt">fliː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/flee-us-male.mp3" data-audio-us-female="/audios/us/flee-us-female.mp3"></span>
-> * <span class="pho">ccvc</span> - *speed* <span class="pho alt">spiːd</span><span class="speak-word-inline" data-audio-us-male="/audios/us/speed-us-male.mp3" data-audio-us-female="/audios/us/speed-us-female.mp3"></span>
-> * <span class="pho">ccvcc</span> - *thrust* <span class="pho alt">θrʌst</span><span class="speak-word-inline" data-audio-us-male="/audios/us/thrust-us-male.mp3" data-audio-us-female="/audios/us/thrust-us-female.mp3"></span>
-> * <span class="pho">ccvccc</span> - *flexed* <span class="pho alt">flekst</span><span class="speak-word-inline" data-audio-us-male="/audios/us/flexed-us-male.mp3" data-audio-us-female="/audios/us/flexed-us-female.mp3"></span>
-> * <span class="pho">cccv</span> - *spray* <span class="pho alt">spreɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/spray-us-male.mp3" data-audio-us-female="/audios/us/spray-us-female.mp3"></span>
-> * <span class="pho">cccvc</span> - *spring* <span class="pho alt">sprɪŋ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/spring-us-male.mp3" data-audio-us-female="/audios/us/spring-us-female.mp3"></span>
-> * <span class="pho">cccvcc</span> - *splashed* <span class="pho alt">splæʃt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/splashed-us-male.mp3" data-audio-us-female="/audios/us/splashed-us-female.mp3"></span>
-> * <span class="pho">cccvccc</span> - *scrounged* <span class="pho alt">skraʊndʒd</span><span class="speak-word-inline" data-audio-us-male="/audios/us/scrounged-us-male.mp3" data-audio-us-female="/audios/us/scrounged-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.3.2-stress.md b/1000-hours/sounds-of-american-english-old/2.3.2-stress.md
deleted file mode 100644
index 05e8a80e..00000000
--- a/1000-hours/sounds-of-american-english-old/2.3.2-stress.md
+++ /dev/null
@@ -1,135 +0,0 @@
-# 2.3.2. 重音（Stress）
-
-当一个词汇由一个以上的音节构成之时，其中的某个音节可能带有重音（*stress*），在音标中使用 <span class="pho">ˈ</span> 作为标记。
-
-When a word contains more than one syllable, one of those syllables may carry the *stress*, marked by <span class="pho">ˈ</span> in phonetic notation.
-
-一个多音节词汇中，最多只有一个重音音节，但，可能还有另外一些音节是**次重音**（*secondary stress*），在音标中使用 <span class="pho">ˌ</span> 作为标记。比如，*serendipity* <span class="pho alt">ˌserənˈdɪpət̬i</span><span class="speak-word-inline" data-audio-us-male="/audios/us/serendipity-us-male.mp3" data-audio-us-female="/audios/us/serendipity-us-female.mp3"></span>，有一个**重音**和一个**次重音**。而 *[Pneumonoultramicroscopicsilicovolcanoconiosis](https://en.wikipedia.org/wiki/Pneumonoultramicroscopicsilicovolcanoconiosis)* 总计有 19 个音节，其中 7 个是次重音，唯一的重音是 <span class="pho">oʊ</span>……
-
-In a multisyllabic word, there is *only one* syllable with *primary stress*. However, there may be other syllables with *secondary stress*, marked by <span class="pho">ˌ</span> in phonetic notation. For instance, *serendipity* <span class="pho alt">ˌserənˈdɪpət̬i</span><span class="speak-word-inline" data-audio-us-male="/audios/us/serendipity-us-male.mp3" data-audio-us-female="/audios/us/serendipity-us-female.mp3"></span> has one primary stress and one secondary stress. On the other hand, the word *[Pneumonoultramicroscopicsilicovolcanoconiosis](https://en.wikipedia.org/wiki/Pneumonoultramicroscopicsilicovolcanoconiosis)* consists of *19* syllables in total, with *7* carrying secondary stress and the *sole* primary stress falling on <span class="pho">oʊ</span>.
-
-在学习英文的时候，亚洲人特别需要注意的是，要从心理上纠正一个对应关系，“英文音节 - 字”，而不是 “英文单词 - 字” —— 亚洲文字，无论是中文、日文还是韩文，所有的字都是单音节构成。
-
-What Asian learners of English must be especially mindful of is to mentally correct the correlation from "*English syllable - Asian Character*" instead of "English word - Asian Character". This is because all characters in Asian languages, whether Chinese, Japanese, or Korean, are composed of single syllables.
-
-*individual* <span class="pho alt">ˌɪndəˈvɪdʒuəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/individual-us-male.mp3" data-audio-us-female="/audios/us/individual-us-female.mp3"></span> 这一个单词，总计 *5* 个音节，即，相当于 *5* 个汉字的长度…… 对比以下句子的音节数量：
-
-The word *individual* <span class="pho alt">ˌɪndəˈvɪdʒuəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/individual-us-male.mp3" data-audio-us-female="/audios/us/individual-us-female.mp3"></span> has a total of *5* syllables, which is equivalent to the length of *5* Chinese characters. Consider the comparison between the number of syllables in the following sentences
-
-> * 人们看法各不相同。<span class="pho">[Rénmen kànfǎ gè bù xiāngtóng]</span> —— 总计 *8* 个字，*8* 个音节。
-> * 人们看法各不相同。<span class="pho">[Rénmen kànfǎ gè bù xiāngtóng]</span> - *8 characters in Chinese, 8 syllables*.
-> * People's opinions vary from individual to individual. <span class="pho alt">ˈpiːpəlz əˈpɪnjənz ˈveri frɑːm ˌɪndəˈvɪdʒuəl tuː ˌɪndəˈvɪdʒuəl</span> —— 总计 *7* 个单词，*19* 个音节。
-> * People's opinions vary from individual to individual. <span class="pho alt">ˈpiːpəlz əˈpɪnjənz ˈveri frɑːm ˌɪndəˈvɪdʒuəl tuː ˌɪndəˈvɪdʒuəl</span> - *7* words in English, *19* syllables.
-
-这个对应关系的纠正很重要，因为这个对应关系在最底层影响连贯声音的理解方式。
-
-Recognizing this correlation is crucial as it fundamentally affects how we comprehend the flow of sounds in a sentence.
-
-另外一个重点在于，英文的音节有**重音**、**次重音**、**非重音**的区别，这一点也和亚洲语言明显不同。
-
-Another crucial point is that English syllables have varying degrees of stress: *primary stress*, *secondary stress*, and the *unstressed*, which is noticeably different from Asian languages.
-
-5 个汉字（或者日文字、韩文字）排在一起大概是这样的：
-
-When 5 Chinese characters (or Japanese or Korean characters) are lined up, it might look like this:
-
-![5-chars](/images/5-chars.svg)
-
-但，由 5 个音节构成的词汇 *individual* 相应应该是这样的：
-
-However, the word *individual*, which is composed of 5 syllables, would likely be represented like this:
-
-![5-syllables](/images/5-syllables.svg)
-
-英语里除了**重音**、**次重音**、**非重音**之外，还有**弱音**，比如被弱化成 <span class="pho">ə</span> 的 *schwa*。
-
-In English, in addition to primary stress, secondary stress, and unstressed syllables, we also have weakly pronounced syllables, like the schwa (<span class="pho">ə</span>) sound that occurs when syllables are reduced.
-
-细细体会 *individual* <span class="pho alt">ˌɪndəˈvɪdʒuəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/individual-us-male.mp3" data-audio-us-female="/audios/us/individual-us-female.mp3"></span> 这个词，如果每个音节都清晰地用同样的强度读出来的话，应该是 <span class="pho alt">ɪn-dɪ-vɪ-dʒju-əl</span>…… 这里面，第 2 个音节 <span class="pho alt">dɪ</span>里的元音 <span class="pho">ɪ</span> 被弱化为 <span class="pho">ə</span>；另外，第 4 个音节 <span class="pho alt">dʒu</span> 里的元音 <span class="pho">ju</span> 也被弱化成了 <span class="pho">ə</span>，但保留了 <span class="pho">u</span> 的音色；而处于音节末尾的 <span class="pho">l</span>，之前自带着轻微的 <span class="pho">ə</span>，于是连成了很轻的 <span class="pho">ʷᵊl</span>……
-
-Let's dig deep into the word *individual*, for example, it's pronounced as <span class="pho alt">ˌɪndəˈvɪdʒuəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/individual-us-male.mp3" data-audio-us-female="/audios/us/individual-us-female.mp3"></span>. If each syllable was placed equal stress, it would sound something like /ɪn-dɪ-vɪ-dʒju-əl/... Within this pronunciation, the vowel <span class="pho">ɪ</span> in the second syllable <span class="pho alt">dɪ</span> is reduced to the schwa sound, <span class="pho">ə</span>; likewise, the vowel <span class="pho">ju</span> in the fourth syllable <span class="pho alt">dʒu</span> is also reduced to <span class="pho">ə</span>, but retains the coloration of <span class="pho">u</span>. The <span class="pho">l</span> at the end of the syllable, which originally carries a slight <span class="pho">ə</span> sound, thus becomes a very light <span class="pho">ʷᵊl</span>...
-
-![5-syllables-individual](/images/5-syllables-individual.svg)
-
-英文的元音有长短之分。需要注意的是：当一个**短元音**构成的**音节**是**重音**的时候，该音节会自然而然读得更长一些，比如 *city* 或者 *silly* 之中的第一个重音音节 <span class="pho alt">ˈsɪ</span> —— 可能是因为 <span class="pho">s</span> 音拉得更长；再比如，*Thanks, I owe you a big one.* 这句话里的 *big* —— 可能是因为 <span class="pho">bɪg</span> 这个词（**音节**）的**音调**（pitch, [2.5.1](2.5.1-pitch)）拉高，或者干脆是 <span class="pho">ɪ</span> 这个**短元音**拉长……
-
-In English, vowel sounds can vary in length. It's interesting to note that when a syllable with a short vowel sound is *stressed*, it's naturally pronounced a bit longer. For example, the first stressed syllable in words like *city* or *silly*, <span class="pho alt">ˈsɪ</span> may be extended due to the drawn-out <span class="pho">s</span> sound. Similarly, the word *big* in the sentence "*Thanks, I owe you a big one*," may be elongated because the pitch of the syllable <span class="pho">bɪg</span> is raised or simply because the short vowel <span class="pho">ɪ</span> is stretched out.
-
-有些时候，同样的词汇，因**重音位置**不同会产生**词义**或**词性**的变化。比如，*address*, <span class="pho alt">ˈædres</span><span class="speak-word-inline" data-audio-us-female="/audios/us/address-noun.mp3"></span> 是名词，“地址”；<span class="pho alt">əˈdres</span><span class="speak-word-inline" data-audio-us-male="/audios/us/address-verb.mp3"></span> 是动词，“强调”；再比如，*record*，可以读作 <span class="pho alt">ˈrekɚd</span><span class="speak-word-inline" data-audio-us-female="/audios/us/record-noun.mp3"></span> 或 <span class="pho alt">rɪˈkɔːrd</span><span class="speak-word-inline" data-audio-us-female="/audios/us/record-verb.mp3"></span>，前者是名词，后者是动词。
-
-At times, the same word can bear different meanings or parts of speech due to the varying placement of the *stress*. For example, the word *address* when pronounced as <span class="pho alt">ˈæˌdres</span><span class="speak-word-inline" data-audio-us-female="/audios/us/address-noun.mp3"></span> is a *noun*, meaning *place of residence*. However, when pronounced as <span class="pho alt">əˈdres</span><span class="speak-word-inline" data-audio-us-male="/audios/us/address-verb.mp3"></span>, it is a *verb*, indicating to *highlight* or *bring attention to*. And *record* can be pronounced as <span class="pho alt">ˈrekɚd</span><span class="speak-word-inline" data-audio-us-female="/audios/us/record-noun.mp3"></span> or <span class="pho alt">rɪˈkɔːrd</span><span class="speak-word-inline" data-audio-us-female="/audios/us/record-verb.mp3"></span>. The former is a *noun*, while the latter is a *verb*.
-
-类似的还有很多，比如以下常见词汇[^1]：
-
-Note, the same word, when pronounced with stress on different syllables, can change its part of speech. Consider the following common words as examples:
-
-| Noun                                                                                                              | Verb                                                                                                             |
-| ----------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------- |
-| 'conduct <span class="pho alt">ˈkɑːndʌkt</span>   <span class="speak-word-inline" data-audio-us-male="/audios/us/conduct-noun.mp3"></span> | con'duct <span class="pho alt">kənˈdʌkt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/conduct-verb.mp3"></span>    |
-| 'conflict <span class="pho alt">ˈkɑːnflɪkt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/conflict-noun.mp3"></span> | con'flict <span class="pho alt">kənˈflɪkt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/conflict-verb.mp3"></span> |
-| 'convert <span class="pho alt">ˈkɑːnvɝːt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/convert-noun.mp3"></span>    | con'vert <span class="pho alt">kənˈvɝːt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/convert-verb.mp3"></span>    |
-| 'digest <span class="pho alt">ˈdaɪdʒest</span><span class="speak-word-inline" data-audio-us-male="/audios/us/digest-noun.mp3"></span>      | di'gest <span class="pho alt">daɪˈdʒest</span><span class="speak-word-inline" data-audio-us-male="/audios/us/digest-verb.mp3"></span>     |
-| 'permit <span class="pho alt">ˈpɝːmɪt</span><span class="speak-word-inline" data-audio-us-female="/audios/us/permit-noun.mp3"></span>      | per'mit <span class="pho alt">pɚˈmɪt</span><span class="speak-word-inline" data-audio-us-female="/audios/us/permit-verb.mp3"></span>      |
-| 'rebel <span class="pho alt">ˈrebəl</span><span class="speak-word-inline" data-audio-us-female="/audios/us/rebel-noun.mp3"></span>         | re'bel <span class="pho alt">rɪˈbel</span><span class="speak-word-inline" data-audio-us-female="/audios/us/rebel-verb.mp3"></span>        |
-| 'subject <span class="pho alt">ˈsʌbdʒekt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/subject-noun.mp3"></span>    | sub'ject <span class="pho alt">səbˈdʒekt</span><span class="speak-word-inline" data-audio-us-female="/audios/us/subject-verb.mp3"></span> |
-
-在随后的章节里我们会涉及到重音音节的另外一个重点 —— 音调（*tone*，[2.5.2](2.5.2-tone)）。
-
-In the upcoming sections, we'll be covering another important aspect of stressed syllables — tone ([2.5.2](2.5.2-tone)).
-
-不妨逐个练习一下以下常用多音节词汇，注意**重音**、**次重音**，以及**非重音**和**弱音** <span class="pho">ə</span>（*schwa*）：
-
-Let's practice the pronunciation of the following commonly used multi-syllable words one by one. Pay attention to the *primary stress*, *secondary stress*, as well as *unstressed*, or *weak* <span class="pho">ə</span> (schwa) sounds:
-
-> * *accommodate* <span class="pho alt">əˈkɑːmədeɪt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/accommodate-us-male.mp3" data-audio-us-female="/audios/us/accommodate-us-female.mp3"></span>
-> * *anniversary* <span class="pho alt">ˌænəˈvɝːsɚi</span><span class="speak-word-inline" data-audio-us-male="/audios/us/anniversary-us-male.mp3" data-audio-us-female="/audios/us/anniversary-us-female.mp3"></span>
-> * *anticipate* <span class="pho alt">ænˈtɪsəpeɪt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/anticipate-us-male.mp3" data-audio-us-female="/audios/us/anticipate-us-female.mp3"></span>
-> * *appreciate* <span class="pho alt">əˈpriːʃieɪt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/appreciate-us-male.mp3" data-audio-us-female="/audios/us/appreciate-us-female.mp3"></span>
-> * *beautiful* <span class="pho alt">ˈbjuːt̬əfəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/beautiful-us-male.mp3" data-audio-us-female="/audios/us/beautiful-us-female.mp3"></span>
-> * *celebration* <span class="pho alt">ˌseləˈbreɪʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/celebration-us-male.mp3" data-audio-us-female="/audios/us/celebration-us-female.mp3"></span>
-> * *characteristic* <span class="pho alt">ˌkerəktəˈrɪstɪk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/characteristic-us-male.mp3" data-audio-us-female="/audios/us/characteristic-us-female.mp3"></span>
-> * *communication* <span class="pho alt">kəˌmjuːnəˈkeɪʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/communication-us-male.mp3" data-audio-us-female="/audios/us/communication-us-female.mp3"></span>
-> * *determination* <span class="pho alt">dɪˌtɝːmɪˈneɪʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/determination-us-male.mp3" data-audio-us-female="/audios/us/determination-us-female.mp3"></span>
-> * *discovery* <span class="pho alt">dɪˈskʌvɚi</span><span class="speak-word-inline" data-audio-us-male="/audios/us/discovery-us-male.mp3" data-audio-us-female="/audios/us/discovery-us-female.mp3"></span>
-> * *encouragement* <span class="pho alt">ɪnˈkɝːɪdʒmənt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/encouragement-us-male.mp3" data-audio-us-female="/audios/us/encouragement-us-female.mp3"></span>
-> * *entrepreneur* <span class="pho alt">ˌɑːntrəprəˈnɝː</span><span class="speak-word-inline" data-audio-us-male="/audios/us/entrepreneur-us-male.mp3" data-audio-us-female="/audios/us/entrepreneur-us-female.mp3"></span>
-> * *environment* <span class="pho alt">ɪnˈvaɪrənmənt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/environment-us-male.mp3" data-audio-us-female="/audios/us/environment-us-female.mp3"></span>
-> * *exaggerate* <span class="pho alt">ɪɡˈzædʒəreɪt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/exaggerate-us-male.mp3" data-audio-us-female="/audios/us/exaggerate-us-female.mp3"></span>
-> * *examination* <span class="pho alt">ɪɡˌzæməˈneɪʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/examination-us-male.mp3" data-audio-us-female="/audios/us/examination-us-female.mp3"></span>
-> * *explanation* <span class="pho alt">ˌekspləˈneɪʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/explanation-us-male.mp3" data-audio-us-female="/audios/us/explanation-us-female.mp3"></span>
-> * *fascinating* <span class="pho alt">ˈfæsəneɪtɪŋ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/fascinating-us-male.mp3" data-audio-us-female="/audios/us/fascinating-us-female.mp3"></span>
-> * *government* <span class="pho alt">ˈɡʌvɚnmənt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/government-us-male.mp3" data-audio-us-female="/audios/us/government-us-female.mp3"></span>
-> * *hospitality* <span class="pho alt">ˌhɑːspɪˈtælət̬i</span><span class="speak-word-inline" data-audio-us-male="/audios/us/hospitality-us-male.mp3" data-audio-us-female="/audios/us/hospitality-us-female.mp3"></span>
-> * *imagination* <span class="pho alt">ɪˌmædʒəˈneɪʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/imagination-us-male.mp3" data-audio-us-female="/audios/us/imagination-us-female.mp3"></span>
-> * *impossible* <span class="pho alt">ɪmˈpɑːsəbəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/impossible-us-male.mp3" data-audio-us-female="/audios/us/impossible-us-female.mp3"></span>
-> * *incredible* <span class="pho alt">ɪnˈkredəbəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/incredible-us-male.mp3" data-audio-us-female="/audios/us/incredible-us-female.mp3"></span>
-> * *independent* <span class="pho alt">ˌɪndɪˈpendənt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/independent-us-male.mp3" data-audio-us-female="/audios/us/independent-us-female.mp3"></span>
-> * *information* <span class="pho alt">ˌɪnfɚˈmeɪʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/information-us-male.mp3" data-audio-us-female="/audios/us/information-us-female.mp3"></span>
-> * *inspiration* <span class="pho alt">ˌɪnspəˈreɪʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/inspiration-us-male.mp3" data-audio-us-female="/audios/us/inspiration-us-female.mp3"></span>
-> * *interesting* <span class="pho alt">ˈɪntrɪstɪŋ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/interesting-us-male.mp3" data-audio-us-female="/audios/us/interesting-us-female.mp3"></span>
-> * *international* <span class="pho alt">ˌɪnt̬ɚˈnæʃənəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/international-us-male.mp3" data-audio-us-female="/audios/us/international-us-female.mp3"></span>
-> * *knowledgeable* <span class="pho alt">ˈnɑːlɪdʒəbəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/knowledgeable-us-male.mp3" data-audio-us-female="/audios/us/knowledgeable-us-female.mp3"></span>
-> * *opportunity* <span class="pho alt">ˌɑːpɚˈtuːnət̬i</span><span class="speak-word-inline" data-audio-us-male="/audios/us/opportunity-us-male.mp3" data-audio-us-female="/audios/us/opportunity-us-female.mp3"></span>
-> * *personality* <span class="pho alt">ˌpɝːsənˈælət̬i</span><span class="speak-word-inline" data-audio-us-male="/audios/us/personality-us-male.mp3" data-audio-us-female="/audios/us/personality-us-female.mp3"></span>
-> * *photography* <span class="pho alt">fəˈtɑːɡrəfi</span><span class="speak-word-inline" data-audio-us-male="/audios/us/photography-us-male.mp3" data-audio-us-female="/audios/us/photography-us-female.mp3"></span>
-> * *professional* <span class="pho alt">prəˈfeʃənəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/professional-us-male.mp3" data-audio-us-female="/audios/us/professional-us-female.mp3"></span>
-> * *recognition* <span class="pho alt">ˌrekəɡˈnɪʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/recognition-us-male.mp3" data-audio-us-female="/audios/us/recognition-us-female.mp3"></span>
-> * *rehabilitation* <span class="pho alt">ˌriːhəˌbɪləˈteɪʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/rehabilitation-us-male.mp3" data-audio-us-female="/audios/us/rehabilitation-us-female.mp3"></span>
-> * *relationship* <span class="pho alt">rɪˈleɪʃənʃɪp</span><span class="speak-word-inline" data-audio-us-male="/audios/us/relationship-us-male.mp3" data-audio-us-female="/audios/us/relationship-us-female.mp3"></span>
-> * *responsibility* <span class="pho alt">rɪˌspɑːnsəˈbɪlət̬i</span><span class="speak-word-inline" data-audio-us-male="/audios/us/responsibility-us-male.mp3" data-audio-us-female="/audios/us/responsibility-us-female.mp3"></span>
-> * *revolutionary* <span class="pho alt">ˌrevəˈluːʃəneri</span><span class="speak-word-inline" data-audio-us-male="/audios/us/revolutionary-us-male.mp3" data-audio-us-female="/audios/us/revolutionary-us-female.mp3"></span>
-> * *satisfaction* <span class="pho alt">ˌsæt̬ɪsˈfækʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/satisfaction-us-male.mp3" data-audio-us-female="/audios/us/satisfaction-us-female.mp3"></span>
-> * *spectacular* <span class="pho alt">spekˈtækjəlɚ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/spectacular-us-male.mp3" data-audio-us-female="/audios/us/spectacular-us-female.mp3"></span>
-> * *temperature* <span class="pho alt">ˈtempɚətʃɚ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/temperature-us-male.mp3" data-audio-us-female="/audios/us/temperature-us-female.mp3"></span>
-> * *transportation* <span class="pho alt">ˌtrænspɚˈteɪʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/transportation-us-male.mp3" data-audio-us-female="/audios/us/transportation-us-female.mp3"></span>
-> * *unbelievable* <span class="pho alt">ˌʌnbɪˈliːvəbəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/unbelievable-us-male.mp3" data-audio-us-female="/audios/us/unbelievable-us-female.mp3"></span>
-> * *understand* <span class="pho alt">ˌʌndɚˈstænd</span><span class="speak-word-inline" data-audio-us-male="/audios/us/understand-us-male.mp3" data-audio-us-female="/audios/us/understand-us-female.mp3"></span>
-> * *understanding* <span class="pho alt">ˌʌndɚˈstændɪŋ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/understanding-us-male.mp3" data-audio-us-female="/audios/us/understanding-us-female.mp3"></span>
-> * *unforgettable* <span class="pho alt">ˌʌnfɚˈɡet̬əbəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/unforgettable-us-male.mp3" data-audio-us-female="/audios/us/unforgettable-us-female.mp3"></span>
-> * *university* <span class="pho alt">ˌjuːnəˈvɝːsət̬i</span><span class="speak-word-inline" data-audio-us-male="/audios/us/university-us-male.mp3" data-audio-us-female="/audios/us/university-us-female.mp3"></span>
-> * *vegetarian* <span class="pho alt">ˌvedʒəˈteriən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/vegetarian-us-male.mp3" data-audio-us-female="/audios/us/vegetarian-us-female.mp3"></span>
-> * *vocabulary* <span class="pho alt">voʊˈkæbjəleri</span><span class="speak-word-inline" data-audio-us-male="/audios/us/vocabulary-us-male.mp3" data-audio-us-female="/audios/us/vocabulary-us-female.mp3"></span>
-> * *vulnerable* <span class="pho alt">ˈvʌlnɚəbəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/vulnerable-us-male.mp3" data-audio-us-female="/audios/us/vulnerable-us-female.mp3"></span>
-> * *wonderfully* <span class="pho alt">ˈwʌndɚfəli</span><span class="speak-word-inline" data-audio-us-male="/audios/us/wonderfully-us-male.mp3" data-audio-us-female="/audios/us/wonderfully-us-female.mp3"></span>
-
-[^1]: Sound files in this list come from [CEPD online edition](https://dictionary.cambridge.org/pronunciation/).
diff --git a/1000-hours/sounds-of-american-english-old/2.4-linking.md b/1000-hours/sounds-of-american-english-old/2.4-linking.md
deleted file mode 100644
index 4677482b..00000000
--- a/1000-hours/sounds-of-american-english-old/2.4-linking.md
+++ /dev/null
@@ -1,24 +0,0 @@
-# 2.4. 连接（Linking）
-
-**音节**是自然语流的最基本单位，于是，自然语流就是由一连串的音节构成的…… 音节就好像是乐曲里的音符。单个音符放在那里往往并无意义，但，很多音符以不同的方式连在一起就能构成美妙的曲调。音节也一样，很多音节以不同的方式连在一起的时候，就有可能构成意义，用以表达或者沟通。
-
-*Syllables* are the basic building blocks of natural speech flow. Just like individual notes in a melody, one syllable alone often lacks meaning, but when strung together in various ways, they can create a wonderful tune. Similarly, when many syllables are combined, they can form meaningful expressions for communication.
-
-英文的音节构成方式很多（[2.3.1](2.3.1-structure)），每个音节围绕着唯一的元音，前后都可能有若干个辅音…… 于是，音节与音节连接在一起的时候，可能出现音素变化的情况总计 *3* 种，因为 “元音 + 辅音” 的组合不会产生音素上的变化：
-
-The construction of syllables in English is varied, each centering around a unique vowel that can be surrounded by several consonants. When syllables are linked together, there are *3* possible combinations, in which phonemes might well have variations, since the combination of a "vowel + consonant" doesn't result in changes to the phonemes.:
-
-> * 辅音 + 元音
-> * Consonant + Vowel
-> * 辅音 + 辅音
-> * Consonant + Consonant
-> * 元音 + 元音
-> * Vowel + Vowel
-
-以上每一种组合都可能产生很多**音素上的变化**。在母语习得的过程中，这些变化是经年累月潜移默化学会的；格外有趣的是，母语使用者对这些细节虽然已经非常熟练，却无法说出具体的操作方法论。学外语的时候不一样 —— 尤其是已经识字的成年人 —— 可以参考语言学家们研究整理过的方法论，进而注意到每个细节，而后再通过反复逐个突破。
-
-Each combination above can lead to a series of *phonetic variations*. These nuances are subtly acquired over years in our native language learning process. Interestingly, while natives can use these details proficiently, they often cannot articulate exactly how they do it. However, when learning a foreign language - especially for literate adults - we can refer to strategies developed by linguists, paying attention to each detail and making breakthroughs through repetition.
-
-需要注意的是，当我们讨论多个音节组合在一起的时候，有两种情况。第一种情况是**多音节词汇** —— 当然是连着的一串音节。而另外一种情况其实也同样常见，在自然语流中更多的是多个词汇组合在一起构成的**意群** —— 实际上也是连着的一串音节。
-
-It's important to note that when discussing syllables strung together, there are two scenarios. The first is *polysyllabic words*, which are, of course, a series of linked syllables. The other common case involves *meaning groups* - combinations of several words that form a continuous string of syllables. Both are commonly found in natural speech flow.
diff --git a/1000-hours/sounds-of-american-english-old/2.4.1-stop.md b/1000-hours/sounds-of-american-english-old/2.4.1-stop.md
deleted file mode 100644
index 8c4dc71a..00000000
--- a/1000-hours/sounds-of-american-english-old/2.4.1-stop.md
+++ /dev/null
@@ -1,78 +0,0 @@
-# 2.3.3 顿与停（Stop and Pause）
-
-在讨论**连接**（_linking_）之前有必要先研究一下**顿**（_stop_）与**停**（_pause_）—— 这一步至关重要、不可或缺。（为了便于理解，在中文表述中，我们用 “停顿” 表示 “顿”，用 “暂停” 表示 “停”。）
-
-Before delving into the concepts of _linking_ words, it's essential to first understand _stops_ and _pauses_, which is a crucial step and can't be overlooked.
-
-在自然语流中，多音节词汇里常常夹杂着**停顿**（_stop_）—— 这是很多初学者干脆感受不到的，所以，他们不是忽略了那些停顿，而是可能压根就不知道某些地方竟然存在停顿。
-
-In natural speech flow, many polysyllabic words are often peppered with _breaks_. This is something many beginners might not even notice, not because they ignore these breaks, but because they might not realize there are supposed to be breaks in certain places.
-
-一个常见的停顿来自于**重读音节**。当我们想要强调某个音节的时候，为了能把它读得相对较重，在此之前往往需要**停顿**一下 —— 做个准备。
-
-When we want to emphasize a syllable, we often need to _stop_ briefly before it to prepare for the pronunciation.
-
-比如，你可以试着读一下 _absolutely_ <span class="pho alt">ˌæbsəˈluːtli</span><span class="speak-word-inline" data-audio-us-male="/audios/us/absolutely-us-male.mp3" data-audio-us-female="/audios/us/absolutely-us-female.mp3"></span>…… 为了把 <span class="pho alt">luː</span> 这个音节读成**重音**（顺带说，这是个长元音），你可能就会不由自主地在发出 <span class="pho">sə</span> 之后略微**停顿**一下…… 拿之前的例子 _individual_ <span class="pho alt">ˌɪndəˈvɪdʒuəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/individual-us-male.mp3" data-audio-us-female="/audios/us/individual-us-female.mp3"></span> 再试一下，若是在 <span class="pho alt">vɪ</span> 之前略微**停顿**一下，就能相对更为轻松地将它读成**重音**。
-
-Take the word _absolutely_ <span class="pho alt">ˌæbsəˈluːtli</span><span class="speak-word-inline" data-audio-us-male="/audios/us/absolutely-us-male.mp3" data-audio-us-female="/audios/us/absolutely-us-female.mp3"></span> for instance. To _stress_ the <span class="pho alt">luː</span> syllable, which is long, you might find yourself involuntarily stopping slightly after pronouncing <span class="pho">sə</span>. The same practice applies to the word _individual_ <span class="pho alt">ˌɪndəˈvɪdʒuəl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/individual-us-male.mp3" data-audio-us-female="/audios/us/individual-us-female.mp3"></span>, which you've practiced before. A brief stop before <span class="pho alt">vɪ</span> makes it relatively easier to stress.
-
-另外一个更为常见的**停顿**相对比较微妙，它就在那里，可不仅听不到，也看不到。
-
-Another frequent stop is more subtle. It's there, but you can't see or hear it.
-
-比如，在 _hotdog_ 这个词里，<span class="pho">t</span> 的声音是听不到的，但，它的舌尖动作却是**完整**的，所以，能够听到的不是 <span class="pho alt">ˈhɑtˌdɔg</span>，也不是 <span class="pho alt">ˈhɑˌdɔg</span>，而是 <span class="pho alt">ˈhɑt̚ ˌdɔg</span><span class="speak-word-inline" data-audio-us-male="/audios/us/hotdog-us-male.mp3" data-audio-us-female="/audios/us/hotdog-us-female.mp3"></span> —— 这里的 <span class="pho">t̚</span> 表示因 <span class="pho">t</span> 的舌尖动作完整却没有发出任何声音而产生的**停顿**。你可以再试试 _network_ <span class="pho alt">ˈnetˌwərk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/network-us-male.mp3" data-audio-us-female="/audios/us/network-us-female.mp3"></span> 这个词 —— 这里面的 <span class="pho">t</span> 也是同样的机制。（注意，也有人用喉塞音读这里的 <span class="pho">t</span>）
-
-Consider the word _hotdog_. You can't hear the <span class="pho">t</span>, but the articulation is complete. So instead of hearing <span class="pho alt">ˈhɑtˌdɔg</span> or <span class="pho alt">ˈhɑˌdɔg</span>, you hear <span class="pho alt">ˈhɑt̚ ˌdɔg</span><span class="speak-word-inline" data-audio-us-male="/audios/us/hotdog-us-male.mp3" data-audio-us-female="/audios/us/hotdog-us-female.mp3"></span> – the <span class="pho">t̚ </span> represents a stop created by the <span class="pho">t</span> sound's complete articulation without any audible output. Try the same with _network_ <span class="pho alt">ˈnetˌwərk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/network-us-male.mp3" data-audio-us-female="/audios/us/network-us-female.mp3"></span> – the <span class="pho">t</span> applies the same principle. (Note, some people pronounce the <span class="pho">t</span> in this context using a _glottal stop_.)
-
-这类**停顿**（_stop_），也叫**塞音**，最常见的有以下几种：
-
-There are several types of _stops_ in English:
-
-> - 唇塞音：<span class="pho">p</span>、<span class="pho">b</span>、<span class="pho">m</span>、<span class="pho">f</span>、<span class="pho">v</span> —— _I just cannot hel**p** myself_. <span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-just-cannot-alloy.mp3" data-audio-us-female="/audios/us/sentence-just-cannot-nova.mp3"></span> 第四个单词 <span class="pho alt">help</span> 末尾的 <span class="pho">p</span> 就是一个唇塞音。
-> - **Bilabial stop**: As in _I just cannot hel**p** myself_ <span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-just-cannot-alloy.mp3" data-audio-us-female="/audios/us/sentence-just-cannot-nova.mp3"></span>, the <span class="pho">p</span> in <span class="pho alt">help</span> is a labial stop.
-> - 齿塞音：<span class="pho">θ</span>、<span class="pho">ð</span> —— _I wish the pa**th** to success was smoother._<span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-wish-the-alloy.mp3" data-audio-us-female="/audios/us/sentence-wish-the-nova.mp3"></span> 第四个单词 <span class="pho alt">pæθ</span> 末尾的 <span class="pho">θ</span> 就是一个齿塞音。
-> - **Dental stop**: <span class="pho">θ</span>, <span class="pho">ð</span> - As in *I wish the *pa**th\*** to success was smoother\*<span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-wish-the-alloy.mp3" data-audio-us-female="/audios/us/sentence-wish-the-nova.mp3"></span>, the final <span class="pho">θ</span> in <span class="pho alt">pæθ</span> is a dental stop.
-> - 龈塞音: <span class="pho">t</span>、<span class="pho">d</span> —— _He trie**d** to discuss his idea with his boss._<span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-tried-to-alloy.mp3" data-audio-us-female="/audios/us/sentence-tried-to-nova.mp3"></span> 第二个单词 <span class="pho alt">traɪd</span> 末尾的 <span class="pho">d</span> 就是一个龈塞音。
-> - **Alveolar stop**: <span class="pho">t</span>, <span class="pho">d</span> - As in *He *trie**d\*** to discuss his idea with his boss\*<span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-tried-to-alloy.mp3" data-audio-us-female="/audios/us/sentence-tried-to-nova.mp3"></span>, where the final <span class="pho">d</span> in <span class="pho alt">traɪd</span> is an alveolar stop.
-> - 喉塞音：<span class="pho">k</span>, <span class="pho">g</span>, <span class="pho">t</span> —— IPA 里用 <span class="pho">ʔ</span>标注。 _I don't thin**k** that is true._<span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-don't-think-alloy.mp3" data-audio-us-female="/audios/us/sentence-don't-think-nova.mp3"></span> 第三个单词 _think_ 末尾的 <span class="pho">k</span> 就是一个喉塞音，<span class="pho alt">θɪŋʔ ðæt</span>。 _uh-oh_ <span class="pho alt">ɑʔoʊ</span><span class="speak-word-inline" data-audio-us-female="/audios/us/Uh-Oh.mp3"></span> 是另外一个例子…… <span class="pho">t</span> 也有可能用这个喉塞音，比如，_utmost_ <span class="pho alt">ˈʌʔˌmoʊst</span><span class="speak-word-inline" data-audio-us-male="/audios/us/utmost-us-male.mp3" data-audio-us-female="/audios/us/utmost-us-female.mp3"></span>，或者 <span class="pho alt">ˈneʔwɝːk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/network-us-male.mp3" data-audio-us-female="/audios/us/network-us-female.mp3"></span>。
-> - **Glottal stop**: <span class="pho">k</span>, <span class="pho">g</span>, <span class="pho">t</span> - In the International Phonetic Alphabet (IPA), the glottal stop is represented by the symbol <span class="pho">ʔ</span>. Take the sentence _I don't think that's true_<span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-don't-think-alloy.mp3" data-audio-us-female="/audios/us/sentence-don't-think-nova.mp3"></span> for example. At the end of the word _think_, there's a glottal stop, as in <span class="pho alt">θɪŋʔ ðæt</span>. Another example is the word _uh-oh_ <span class="pho alt">ɑʔoʊ</span><span class="speak-word-inline" data-audio-us-female="/audios/us/Uh-Oh.mp3"></span>. Also, <span class="pho">t</span> can sometimes be replaced with a glottal stop, as in _utmost_ <span class="pho alt">ˈʌʔˌmoʊst</span><span class="speak-word-inline" data-audio-us-male="/audios/us/utmost-us-male.mp3" data-audio-us-female="/audios/us/utmost-us-female.mp3"></span> or _network_ <span class="pho alt">ˈneʔwɝːk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/network-us-male.mp3" data-audio-us-female="/audios/us/network-us-female.mp3"></span>.
-
-不管是哪一种，大多都是因为之前的一个辅音**虽然并未发出声音却动作完整**造成的。
-
-Regardless of the type, most of such stops occur when a previous consonant is fully articulated without actually producing sound.
-
-除了**停顿**（_stop_）之外，一句话可能会被分为若干个**意群**（_thought group_），意群之间总是有着明显的**暂停**（_pause_）。
-
-Apart from _stops_, a sentence can be divided into several _thought groups_, each separated by an obvious _pause_.
-
-先听听这段话的录音[^1]：
-
-Check out the recording of this stentence:
-
-> _Yet, it is a fact of life that an unlettered peasant is considered ignorant._ <span class="speak-word-inline" data-audio-us-male="/audios/us/yet-it-is-a-fact.mp3"></span>
->
-> 以下是这段音频的 _Waveform_（波谱）和 _Pitch Contour_（音高变化）：
->
-> Here are the Waveform and Pitch Contour for this audio clip:
->
-> ![yet-it-is-a-fact-of-life](/images/yet-it-is-a-fact-of-life.png)
->
-> - _Pitch Contour_ 截图来自学习辅助工具 [Enjoy](https://github.com/zuodaotech/everyone-can-use-english)。
-> - The screenshot of the Pitch Contour is from the learning aid App [Enjoy](https://github.com/zuodaotech/everyone-can-use-english).
-
-在 Waveform 里我们可以清楚地看到，这句话里有两处明显的停顿（用 <span class="pho">|</span> 标注）：
-
-In the Waveform, we can clearly see two significant pauses (marked with <span class="pho">|</span>) in this sentence:
-
-> _Yet, | it is a fact of life | that an unlettered peasant is considered ignorant._ <span class="speak-word-inline" data-audio-us-male="/audios/us/yet-it-is-a-fact.mp3"></span>
-
-**停顿**（_stop_）与**暂停**（_pause_）可以用**可否换气**进行区分：
-
-The distinction between _stop_ and _pause_ can be clarified by whether or not one has the opportunity to take a breath:
-
-> - 音节之间的**停顿**（_stop_）通常是不用甚至不能换气的；
-> - A _stop_ usually occurs between syllables where you don't need to, and often can't, take a breath;
-> - 意群之间的**暂停**（_pause_）是可以换气的 —— 当然若非必要也可以不换气；
-> - A _pause_ typically happens between thought groups, where you have the opportunity to take a breath - although it's not always necessary to do so.
-
-[^1]: This audio clip is extracted from the Audible edition of _Knowledge and Decisions_ by Thomas Sowell.
diff --git a/1000-hours/sounds-of-american-english-old/2.4.2-cv.md b/1000-hours/sounds-of-american-english-old/2.4.2-cv.md
deleted file mode 100644
index d38cc6e0..00000000
--- a/1000-hours/sounds-of-american-english-old/2.4.2-cv.md
+++ /dev/null
@@ -1,47 +0,0 @@
-# 2.4.2 辅音 + 元音（Consonant + Vowel）
-
-在词汇内部，“辅音 + 元音” 当然可以构成一个音节；在同一个**意群**（thought group）中，如果**以辅音结尾的词汇**遇到**以元音开头的词汇**的话，那么前一个词末尾的**辅音**和后一个词开头的**元音**很可能会连起来读，听起来构成一个**音节**，这种方式叫做**连读**。
-
-A syllable can be formed by a "consonant + vowel" combination within a word. Within the same *thought group*, if a word *ending in a consonant* meets a word *beginning with a vowel*, the final consonant of the first word and the initial vowel of the second word *may well* blend together when spoken, sounding as if they form a single *syllable*, which is often referred to as *linking*.
-
-比如在 *People's opinions vary from individual to individual.*<span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-opinions-vary-alloy.mp3" data-audio-us-female="/audios/us/sentence-opinions-vary-nova.mp3"></span> 在这句话中，*People's* 末尾的 <span class="pho">z</span> 和 *opinions* 开头的 <span class="pho">ə</span> 会连在一起，<span class="pho alt">piː·pəl·zə·ˈpɪ·njənz</span> —— 感觉上是在读一整个由 *5* 个音节构成的词汇一样……
-
-For instance, when saying *People's opinions vary from individual to individual*<span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-opinions-vary-alloy.mp3" data-audio-us-female="/audios/us/sentence-opinions-vary-nova.mp3"></span>, the <span class="pho">s</span> at the end of *People's* and the <span class="pho">ə</span> at the start of *opinions* seamlessly connect, making it sound like a five-syllable word: /pi-pəl-zə-ˈpɪ-njənz/. It feels as if you're pronouncing a single, lengthy word.
-
-这类**连读**中有相当难度乃至于必须刻意练习的其实只有两种，<span class="pho">t</span> 和 <span class="pho">l</span> 构成的连读。
-
-There are two particular types which are quite challenging and require deliberate practice. These involve the use of <span class="pho">t</span> and <span class="pho">l</span>, respectively.
-
-之前提到过，在美式英语里，<span class="pho">t</span> 有个特殊的现象，它夹在两个元音之间的时候会被浊化，被读成弹舌音，用 <span class="pho">t̬</span> 表示，听起来接近 <span class="pho">d</span>…… 比如，在 city <span class="pho alt">ˈsɪt̬i</span><span class="speak-word-inline" data-audio-us-male="/audios/us/city-us-male.mp3" data-audio-us-female="/audios/us/city-us-female.mp3"></span> 这个词汇里， <span class="pho">t</span> 就夹在两个元音之间。
-
-It is previously mentioned that in American English, the <span class="pho">t</span> sound has a unique characteristic. When it's sandwiched between two vowels, it's often voiced with an *alveolar flapping*, creating a sound very close to <span class="pho">d</span>. This is represented as <span class="pho">t̬</span>. For example, in the word *city* <span class="pho">/ˈsɪt̬i</span>/<span class="speak-word-inline" data-audio-us-male="/audios/us/city-us-male.mp3" data-audio-us-female="/audios/us/city-us-female.mp3"></span>, the <span class="pho">t</span> is between two vowels.
-
-在自然语流里，同一个意群中，经常会出现以 <span class="pho">t</span> 结尾的词汇后面跟着一个以元音开头的词汇，并且，<span class="pho">t</span> 的前面是元音的概率也很高，所以，词汇之间出现 <span class="pho">t</span> 的浊化弹舌音 <span class="pho">t̬</span> 的情况非常普遍。比如，*Get it done.* <span class="pho alt">ɡet̬ ɪt dʌn</span><span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-it-done-alloy.mp3" data-audio-us-female="/audios/us/sentence-it-done-nova.mp3"></span>
-
-In natural speech flow, it's common to find a word ending with <span class="pho">t</span> closely followed by a word beginning with a vowel within the same thought group. Furthermore, there's a high possibility that the <span class="pho">t</span> is preceded by a vowel. Therefore, the occurrence of the flapped <span class="pho">t̬</span> between words is incredibly prevalent. For example: *Get it done.* <span class="pho alt">ɡet̬ ɪt dʌn</span><span class="speak-word-inline" data-audio-us-male="/audios/us/sentence-it-done-alloy.mp3" data-audio-us-female="/audios/us/sentence-it-done-nova.mp3"></span>
-
-<span class="pho">l</span> 构成的连读，对绝大多数人来说，难点在于，如果前一个单词末尾的 <span class="pho">l</span> **舌尖动作不够完整**的话（即，结束的时候舌尖没有贴到龈脊）那么，<span class="pho">l</span> 这个弹舌音就发不出来，无法与后面的元音连上…… 尤其是在没有纠正掉用嘴唇动作替代舌尖动作的错误（乃至于有 <span class="pho">ʊ</span> 的音色）的情况下。
-
-The challenge of linked speech involving <span class="pho">l</span> lies in the tongue's movement. If the tip of the tongue does not make complete contact with the roof of the mouth at the end of a word ending in <span class="pho">l</span>, it's difficult to produce the appropriate sound for the subsequent flapping <span class="pho">l</span> with the following vowel. This is especially true if the habit of substituting the movement of the lips for the action of the tongue hasn't been corrected, leading to a sound colored by <span class="pho">ʊ</span>.
-
-请仔细听一遍以下的录音，注意所有以 <span class="pho">l</span> 作为末尾的音节：
-
-Please listen carefully to the following recording, pay special attention to words ending with <span class="pho">l</span>:
-
-> Whether the *goal of* an insurgency has been to establish the Christian religion in the days of the Roman Empire, to create an interstate commerce commission in nineteenth-century America, or to promote civil rights for minorities in the twentieth century, what a *successful insurgency* does in *institutional or* process terms is to change the incentives and constraints facing others, as well as the incentives and constraints facing themselves and their successors.<span class="speak-word-inline" data-audio-us-male="/audios/us/goal-of.mp3"></span>[^1]
-
-在以上这段录音中，*goal~of*<span class="speak-word-inline" data-audio-us-male="/audios/us/goal-of-1.mp3"></span>, *successful~insurgency*<span class="speak-word-inline" data-audio-us-male="/audios/us/goal-of-2.mp3"></span>, *as well~as*<span class="speak-word-inline" data-audio-us-male="/audios/us/goal-of-3.mp3"></span>, 都有前一个单词末尾的 <span class="pho">l</span> 与后一个单词开头的元音之间轻微的连读。但，*institutional or*<span class="speak-word-inline" data-audio-us-male="/audios/us/goal-of-4.mp3"></span> 之间却没有 —— 因为这两个词汇实际上分别属于前后不同的意群。
-
-In the audio clip above, the phrase *goal~of*<span class="speak-word-inline" data-audio-us-male="/audios/us/goal-of-1.mp3"></span>, *successful~insurgency*<span class="speak-word-inline" data-audio-us-male="/audios/us/goal-of-2.mp3"></span>, and *as well~as*<span class="speak-word-inline" data-audio-us-male="/audios/us/goal-of-3.mp3"></span> all exhibit slight linking between the ending <span class="pho">l</span> of the first word and the vowel at the beginning of the following word. However, there's no such linking between *institutional* and *or*<span class="speak-word-inline" data-audio-us-male="/audios/us/goal-of-4.mp3"></span>. That's because these two words belong to separate thought groups.
-
-初学者容易矫枉过正，想把一切自己遇到的词汇间 “辅音 + 元音” 的组合连起来读…… 请注意，是**很可能**连起来读，但**并不一定**。首先，这多少与个人讲话的习惯有关。更为重要的是，讲话的时候要划分**意群**，意群之间要有**暂停**（*pause*）—— 前一个意群末尾的辅音和下一个意群开头的元音，不应该连读。
-
-Beginners often overcorrect when learning English, trying to merge all "consonant + vowel" combinations they encounter. Remember, it's *possible* to connect sounds, but it's not always *necessary*. This largely depends on personal speaking habits. More importantly, when speaking, one should divide their speech into *thought groups*, pausing between each group. Do not blend the ending consonant of one thought group with the beginning vowel of the next.
-
-> [!Note]
->
-> 目前（2024.03） OpenAI 的 TTS 引擎生成的语音中，*<span class="pho">l</span> + vowels* 的组合总是没有连读效果 —— 也许将来的版本会改进？
->
-> As of now (March 2024), the TTS engine from OpenAI doesn't seem to blend the sound of ending <span class="pho">l</span> with following vowels smoothly. But who knows? Future versions might just improve on this.
-
-[^1]: This audio clip is extracted from the Audible edition of Knowledge and Decisions by Thomas Sowell.
\ No newline at end of file
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-# 2.4.3. 辅音 + 辅音（Consonant + Consonant）
-
-“**辅音 + 辅音**” 的组合需要注意的地方相对较多。
-
-The combination of "consonant + consonant" often requires more attention.
-
-## 2.4.3.1 省音（elision）
-
-“**辅音 + 辅音**” 的组合，常常会造成前一个辅音虽然发声器官（*articulator*）动作完整但并不发声的情况，于是会出现一个既 “看不见” 也 “听不到” 的**停顿**（*stop*，[2.4.1](2.4.1-stop)），之前举过单词内存在这种情况的例子，*hotdog* <span class="pho alt">ˈhɑːtdɑːɡ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/hotdog-us-male.mp3" data-audio-us-female="/audios/us/hotdog-us-female.mp3"></span> 和 *network* <span class="pho alt">ˈnetwɝːk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/network-us-male.mp3" data-audio-us-female="/audios/us/network-us-female.mp3"></span>，再比如，*hard-nosed* <span class="pho alt">hɑːrd-noʊzd</span><span class="speak-word-inline" data-audio-us-male="/audios/us/hard-nosed-us-male.mp3" data-audio-us-female="/audios/us/hard-nosed-us-female.mp3"></span>, *partner* <span class="pho alt">ˈpɑːrtnɚ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/partner-us-male.mp3" data-audio-us-female="/audios/us/partner-us-female.mp3"></span>……
-
-A "consonant + consonant" combination often results in an instance where the first consonant is articulated but not voiced, creating an *invisible and inaudible stop* ([2.4.1](2.4.1-stop)). Examples of this within words include previously mentioned *hotdog* <span class="pho alt">ˈhɑːtdɑːɡ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/hotdog-us-male.mp3" data-audio-us-female="/audios/us/hotdog-us-female.mp3"></span> and *network* <span class="pho alt">ˈnetwɝːk</span><span class="speak-word-inline" data-audio-us-male="/audios/us/network-us-male.mp3" data-audio-us-female="/audios/us/network-us-female.mp3"></span>, as well as *hard-nosed* <span class="pho alt">hɑːrd-noʊzd</span><span class="speak-word-inline" data-audio-us-male="/audios/us/hard-nosed-us-male.mp3" data-audio-us-female="/audios/us/hard-nosed-us-female.mp3"></span>, *partner* <span class="pho alt">ˈpɑːrtnɚ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/partner-us-male.mp3" data-audio-us-female="/audios/us/partner-us-female.mp3"></span>, and so on.
-
-有人把这种现象叫做 **省音**（*elision*）；但，这种说法容易产生误导，因为音的确是省了，但，动作却没省，不仅没有省，**动作还很完整**。
-
-Some refer to this phenomenon as *elision*. While it's true that the sound is dropped, the action of articulation isn't skipped – in fact, it's fully completed.
-
-在意群中，更是经常出现前一个词汇末尾是辅音，后一个词汇开头也是辅音的情况 —— 同样会出现**省音**。
-
-Within a meaning group, it's common for a word to end with a consonant and the following word to begin with one, resulting in *elision*.
-
-## 2.4.3.2. 叠音（geminates）
-
-上一个音节末尾的辅音和下一个音节开头的辅音相同的时候，这一对相同的辅音被称作**叠音**（*geminates*）。在连贯的自然语音中，这两个辅音就只发声一次 —— 但听起来的时候，有可能感受到前一个辅音存在造成细微停顿。它从机制上来看，其实和**省音**（[2.4.3.1](2.4.3-cc#_2-4-3-1-省音-elision)）一样。其实哪怕相邻的两个辅音相似的时候，也会发生同样的现象。
-
-When the same consonant ends one syllable and begins the next, this pair of identical consonants is known as *geminates*. In fluid, natural speech, these two consonants are vocalized only once— yet, you might sense a slight *stop* due to the presence of the previous consonant, and its completion of articulating action. Mechanically, this is similar to *elision* ([2.4.3.1](2.4.3-cc#_2-4-3-1-省音-elision)). This phenomenon also occurs even when two neighboring consonants are just similar, not identical.
-
-比如，*that time*, 不是 <span class="pho">ðæt taɪm/</span>，而是 <span class="pho alt">ðæ·t̬aɪm</span><span class="speak-word-inline" data-audio-us-male="/audios/us/at-that-time-us-male.mp3" data-audio-us-female="/audios/us/at-that-time-us-female.mp3"></span> —— 第一个 <span class="pho">t</span> 由于后面跟着一个辅音，于是产生了**省音**，听不到了，但，该有的停顿却依然在，在这里我们用 <span class="pho">·</span> 代表那个停顿 ；而后，第二个 <span class="pho">t</span> 与第三个 <span class="pho">t</span> 是**叠音**，这两个 <span class="pho">t</span> 只发声一次。又比如，*bad day*, 不是 <span class="pho alt">bæd deɪ</span>，而是 <span class="pho alt">bæ·deɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/a-bad-day-us-male.mp3" data-audio-us-female="/audios/us/a-bad-day-us-female.mp3"></span>。 再比如，*with this*, 不是 <span class="pho alt">wɪθ ðɪs</span>，而是 <span class="pho alt">wɪ·ðɪs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/with-this-us-male.mp3" data-audio-us-female="/audios/us/with-this-us-female.mp3"></span>。
-
-For instance, *at that time* is not pronounced as <span class="pho alt">ðæt taɪm</span>, but as <span class="pho alt">ðæ·t̬aɪm</span><span class="speak-word-inline" data-audio-us-male="/audios/us/at-that-time-us-male.mp3" data-audio-us-female="/audios/us/at-that-time-us-female.mp3"></span>. Here, the first <span class="pho">t</span> is elided because it is followed by another consonant, so you can't hear it. However, the expected pause is still there, represented by <span class="pho">·</span>. Then, the second <span class="pho">t</span> and the third <span class="pho">t</span> form a geminate, and are vocalized only once. Similarly, *bad day* is not pronounced as <span class="pho alt">bæd deɪ</span>, but as <span class="pho alt">bæ·deɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/a-bad-day-us-male.mp3" data-audio-us-female="/audios/us/a-bad-day-us-female.mp3"></span>; *with this*, is not <span class="pho alt">wɪθ ðɪs</span>，but <span class="pho alt">wɪ·ðɪs</span><span class="speak-word-inline" data-audio-us-male="/audios/us/with-this-us-male.mp3" data-audio-us-female="/audios/us/with-this-us-female.mp3"></span>.
-
-## 2.4.3.3. 同化（assimilation）
-
-同化（*assimilation*）主要有两种情况：
-
-Assimilation, in English pronunciation, primarily happens in two key scenarios:
-
-> * <span class="pho">t</span> + <span class="pho">j</span> = <span class="pho">tʃ</span>
-> * <span class="pho">d</span> + <span class="pho">j</span> = <span class="pho">dʒ</span>
-
-最常见的比如，*Don't you?* <span class="pho alt">doʊn tʃju?</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Dont-you-us-male.mp3" data-audio-us-female="/audios/us/Dont-you-us-female.mp3"></span>；以及，*Would you?* <span class="pho alt">wʊ dʒju?</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Would-you-us-male.mp3" data-audio-us-female="/audios/us/Would-you-us-female.mp3"></span> 这里的关键在于，<span class="pho">t, d</span> 发声时起始的舌尖位置如果放对了（[2.2.3](2.2.3-td)），它与后面的 <span class="pho alt">ju</span> 连起来的发声就只能如此。
-
-For example, in daily conversation, we often hear *Don't you?* pronounced as <span class="pho alt">doʊn tʃju?</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Dont-you-us-male.mp3" data-audio-us-female="/audios/us/Dont-you-us-female.mp3"></span>; and *Would you?* as <span class="pho alt">wʊ dʒju?</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Would-you-us-male.mp3" data-audio-us-female="/audios/us/Would-you-us-female.mp3"></span>. The key here lies in the position of the tongue tip when pronouncing <span class="pho">t, d</span>. If placed correctly (as explained in [2.2.3](2.2.3-td)), it naturally leads to such pronunciation when followed by <span class="pho alt">ju</span>.
-
-同化主要发生在 <span class="pho">j</span> 这个音上。除了已经讲过的 <span class="pho">j</span> 前面遇到 <span class="pho">t</span> 和 <span class="pho">d</span> 时会产生同化之外，
-
-Assimilation mainly happens when a word ends in <span class="pho">j</span>. Besides the explained cases where <span class="pho">t</span> and <span class="pho">d</span> are followed by <span class="pho">j</span>,
-
-> * <span class="pho">s</span> + <span class="pho">j</span> = <span class="pho">ʃ</span>
-> * <span class="pho">z</span> + <span class="pho">j</span> = <span class="pho">ʒ</span>
-
-比如，<span class="pho">s+j</span> 可能会被读成 <span class="pho">ʃ</span>，<span class="pho">z+j</span> 可能会被读成 <span class="pho">ʒ</span>。再比如，*Miss you so much.* <span class="pho alt">mɪ ʃu səʊ mʌʧ.</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Miss-you-so-much-us-male.mp3" data-audio-us-female="/audios/us/Miss-you-so-much-us-female.mp3"></span>；*It was your job.* <span class="pho alt">ɪt wɒ ʒʊr ʤɒb.</span><span class="speak-word-inline" data-audio-us-male="/audios/us/It-was-your-job-us-male.mp3" data-audio-us-female="/audios/us/It-was-your-job-us-female.mp3"></span>
-
-For instance, the combination <span class="pho">s+j</span> might be pronounced as <span class="pho">ʃ</span>, and <span class="pho">z+j</span> might be pronounced as <span class="pho">ʒ</span>. Here are examples: *Miss you so much* can be pronounced as <span class="pho alt">mɪ ʃu səʊ mʌʧ.</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Miss-you-so-much-us-male.mp3" data-audio-us-female="/audios/us/Miss-you-so-much-us-female.mp3"></span>; *It was your job* can be pronounced as <span class="pho alt">ɪt wɒ ʒʊr ʤɒb.</span><span class="speak-word-inline" data-audio-us-male="/audios/us/It-was-your-job-us-male.mp3" data-audio-us-female="/audios/us/It-was-your-job-us-female.mp3"></span>
-
-请注意，这两组是**可能**，并非一定，并非所有英文母语使用者都如此发音。
-
-However, it's important to note that these are possibilities, not certainties. Not all English native speakers pronounce words this way.
-
-另外一个细节是，<span class="pho">k/g</span> 之前的 <span class="pho">n</span>，可能会被同化为 <span class="pho">ŋ</span>:
-
-> * *ten cups*, <span class="pho alt">ten kʌps</span> → <span class="pho alt">teŋ kʌps</span><span class="speak-word-inline" data-audio-us-male="/audios/us/ten-cups-us-male.mp3" data-audio-us-female="/audios/us/ten-cups-us-female.mp3"></span>
-> * *increase*, <span class="pho alt">ˌɪnˈkris</span> → <span class="pho alt">ˌɪŋˈkris</span><span class="speak-word-inline" data-audio-us-male="/audios/us/increase-us-male.mp3" data-audio-us-female="/audios/us/increase-us-female.mp3"></span>
-> * *brown gate*, <span class="pho alt">braʊn geɪt</span> → <span class="pho alt">braʊŋ geɪt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/brown-gate-us-male.mp3" data-audio-us-female="/audios/us/brown-gate-us-female.mp3"></span>
-
-## 2.4.3.4. 击穿（dropping）
-
-“辅音 + 辅音” 的组合中，如果第二个辅音是 <span class="pho">h</span> 的话，它常常被击穿（*dropping*），因为 <span class="pho">h</span> 原本就是很轻的音，发音时声带并不震动，所以总是自然而然地被前后发音相对更为响亮的声音所掩盖。
-
-In a "consonant + consonant" combination, where the second is <span class="pho">h</span>, the <span class="pho">h</span> sound often gets *dropped*, simply due to its soft nature. This is because the *vocal cords* don't vibrate when pronouncing <span class="pho">h</span>, and it naturally gets overshadowed by the louder sounds before and after.
-
-比如，*Was he hurt?* 三个单词分开读，应该是 <span class="pho alt">wɒz hi həːt</span> 在连贯的语音中，会被读成 <span class="pho alt">wɒzi həːt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Was-he-hurt-us-male.mp3" data-audio-us-female="/audios/us/Was-he-hurt-us-female.mp3"></span> —— 听不到 <span class="pho">h</span>，它被击穿了。
-
-For example, take the sentence *Was he hurt?* If pronounced separately, it should be <span class="pho alt">wɒz hi həːt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Was-he-hurt-us-male.mp3" data-audio-us-female="/audios/us/Was-he-hurt-us-female.mp3"></span>. However, when spoken fluidly, it sounds more like <span class="pho alt">wɒzi həːt</span>; the <span class="pho">h</span> becomes unnoticeable.
-
-很多美国人在 <span class="pho">t</span> 这个音上还有另外一个特殊的习惯，<span class="pho">t</span> 跟在 <span class="pho">n</span> 之后的时候，美国人说话的方式会让我们听不到那个 <span class="pho">t</span>，也就是说，<span class="pho">t</span> 也可能被击穿。比如，他们说 *interview* 的时候你听到的可能是 <span class="pho alt">ˈɪnəˌvju</span><span class="speak-word-inline" data-audio-us-male="/audios/us/interview-us-male.mp3" data-audio-us-female="/audios/us/interview-us-female.mp3"></span>，没有 <span class="pho">t</span>。
-
-Many Americans have a unique habit with the <span class="pho">t</span> sound, especially when it follows <span class="pho">n</span>. Their way of speaking often causes the <span class="pho">t</span> to disappear. For instance, when they say the word *interview*, you might hear <span class="pho alt">ˈɪnəˌvju</span><span class="speak-word-inline" data-audio-us-male="/audios/us/interview-us-male.mp3" data-audio-us-female="/audios/us/interview-us-female.mp3"></span>, without the <span class="pho">t</span>.
-
-另外，<span class="pho">ð</span> 也可能被击穿，基本只发生在 *them* 这个常用词上。比如，*let them* <span class="pho alt">let ðəm</span>, 变成了 <span class="pho alt">let-əm</span>，又由于 <span class="pho">ð</span> 被击穿了之后，<span class="pho">t</span> 等于被夹在了两个元音之间，于是会变成浊化的弹舌音 <span class="pho">t̬</span>，于是，说出来的或者听到的是 <span class="pho alt">let̬əm</span>…… 所以，在快速的自然语流中 *let him* 和 *let them* 实际上几乎没有区别，需要通过上下文确定究竟是 *him* 还是 *them*。
-
-In addition, the <span class="pho">ð</span> sound can also be dropped, primarily in the common word *them*. For example, *let them* <span class="pho alt">let ðəm</span> might become <span class="pho alt">let-əm</span>. When the <span class="pho">ð</span> is dropped, the <span class="pho">t</span> ends up sandwiched between two vowels and turns into the voiced flap <span class="pho">t̬</span>. So, what you say or hear becomes <span class="pho alt">let̬əm</span>. Therefore, in fast natural speech, *let him* and *let them* sound almost identical and only context can determine whether it's *him* or *them*.
-
-## 2.4.3.5 其它（others）
-
-值得一提的是，<span class="pho">m/n</span> + <span class="pho">f/v</span> 的情况。词汇之内我们看过 *comfort* <span class="pho alt">ˈkʌmfɚt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/comfort-us-male.mp3" data-audio-us-female="/audios/us/comfort-us-female.mp3"></span> 和 *conversation* <span class="pho alt">ˌkɑːnvɚˈseɪʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/conversation-us-male.mp3" data-audio-us-female="/audios/us/conversation-us-female.mp3"></span> 的例子（[2.2.13](2.2.13-mnŋ)）。这种情况在意群之内也经常会遇到，比如，*stem from*, 只能读成 <span class="pho alt">sten frəm</span><span class="speak-word-inline" data-audio-us-male="/audios/us/stem-from-us-male.mp3" data-audio-us-female="/audios/us/stem-from-us-female.mp3"></span>……
-
-It's worth mentioning the situation with <span class="pho">m/n</span> followed by <span class="pho">f/v</span>. We've seen examples of this in words like *comfort* <span class="pho alt">ˈkʌmfɚt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/comfort-us-male.mp3" data-audio-us-female="/audios/us/comfort-us-female.mp3"></span> and *conversation* <span class="pho alt">ˌkɑːnvɚˈseɪʃən</span><span class="speak-word-inline" data-audio-us-male="/audios/us/conversation-us-male.mp3" data-audio-us-female="/audios/us/conversation-us-female.mp3"></span>([2.2.13](2.2.13-mnŋ)). This occurrence is often also found within a meaning group. For instance, *stem from* can only be pronounced as <span class="pho alt">sten frəm</span><span class="speak-word-inline" data-audio-us-male="/audios/us/stem-from-us-male.mp3" data-audio-us-female="/audios/us/stem-from-us-female.mp3"></span>.
-
diff --git a/1000-hours/sounds-of-american-english-old/2.4.4-vv.md b/1000-hours/sounds-of-american-english-old/2.4.4-vv.md
deleted file mode 100644
index c3fc8002..00000000
--- a/1000-hours/sounds-of-american-english-old/2.4.4-vv.md
+++ /dev/null
@@ -1,37 +0,0 @@
-# 2.4.4. 元音 + 元音（Vowel + Vowel）
-
-“元音 + 元音” 的组合之中，会出现**加音**（*intrusion*）。
-
-In combinations of "vowel + vowel", an *intrusion* sound may occur.
-
-前一个元音以 <span class="pho">ɪ/i/iː</span> 结尾，会出现加音 <span class="pho">ʲ</span>：
-
-When the first vowel ends in <span class="pho">ɪ/i/iː</span>, an intrusive <span class="pho">ʲ</span> sound emerges:
-
-> - *I am* - <span class="pho alt">ˈaɪ ˈæm</span> ⭢ <span class="pho alt">ˈaɪʲæm</span><span class="speak-word-inline" data-audio-us-male="/audios/us/I-am-us-male.mp3" data-audio-us-female="/audios/us/I-am-us-female.mp3"></span>
-> - *He is* - <span class="pho alt">ˈhiː ˈɪz</span> ⭢ <span class="pho alt">ˈhiːʲɪz</span><span class="speak-word-inline" data-audio-us-male="/audios/us/He-is-us-male.mp3" data-audio-us-female="/audios/us/He-is-us-female.mp3"></span>
-> - *She is* - <span class="pho alt">ˈʃiː ˈɪz</span> ⭢ <span class="pho alt">ˈʃiːʲɪz</span><span class="speak-word-inline" data-audio-us-male="/audios/us/She-is-us-male.mp3" data-audio-us-female="/audios/us/She-is-us-female.mp3"></span>
-> - *They are* - <span class="pho alt">ˈðeɪ ˈɑːr</span> ⭢ <span class="pho alt">ˈðeɪʲɑːr</span><span class="speak-word-inline" data-audio-us-male="/audios/us/They-are-us-male.mp3" data-audio-us-female="/audios/us/They-are-us-female.mp3"></span>
-
-注意：一些以 <span class="pho">i</span> 结尾的动词，使用进行时态的时候，末尾会加上 *ing*，即，<span class="pho alt">ɪŋ</span>。比如，*study* <span class="pho alt">ˈstʌdi</span> 的现在分词形式是 *studying* <span class="pho alt">ˈstʌdi.ɪŋ</span> —— 这里会出现加音 <span class="pho">ʲ</span>，即最后一个音节变成 <span class="pho alt">jɪŋ</span>…… 可是，在自然读音中，它更接近 <span class="pho alt">jəŋ</span>，所以，*studying* 的读音，词典里标注的当然还是 <span class="pho alt">ˈstʌdiɪŋ</span>，但，读出来的更接近 <span class="pho alt">ˈstʌdiʲəŋ</span>。
-
-Here's a note about verbs that end with <span class="pho">i</span>: when you're using these verbs in the present progressive tense, you add *ing* to the end, pronounced as <span class="pho alt">ɪŋ</span>. Take the verb *study* <span class="pho alt">ˈstʌdi</span> for example, which present participle form is *studying* <span class="pho alt">ˈstʌdiɪŋ</span>. There's a subtle addition of a <span class="pho">ʲ</span> sound, making the last syllable sound like <span class="pho alt">jɪŋ</span>. However, in natural pronunciation, it sounds closer to <span class="pho alt">jəŋ</span>. Therefore, even though the pronunciation of *studying* is annotated as <span class="pho alt">ˈstʌdiɪŋ</span> in dictionaries, it should be pronounced more like <span class="pho alt">ˈstʌdiʲəŋ</span>.
-
-再比如：
-
-More examples:
-
-> *applying* *carrying* *crying*
->
-> *denying* *qulifying* *replying*
->
-> *satisfying* *specifying* *spying*
-
-前一个音节以 <span class="pho">ʊ</span> 结尾，比如 <span class="pho">ʊ/uː/aʊ/oʊ</span>，会出现加音 <span class="pho">ʷ</span>：
-
-Similarly, when the preceding syllable ends in <span class="pho">ʊ</span>, such as <span class="pho">ʊ/uː/aʊ/oʊ</span>, an intrusive <span class="pho">ʷ</span> sound appears:
-
-> - *Go away* - <span class="pho alt">ˈɡoʊ əˈweɪ</span> ⭢ <span class="pho alt">ˈɡoʊʷəˈweɪ</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Go-away-us-male.mp3" data-audio-us-female="/audios/us/Go-away-us-female.mp3"></span>
-> - *Do all* - <span class="pho alt">ˈduː ˈɔːl</span> ⭢ <span class="pho alt">ˈduːʷɔːl</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Do-all-us-male.mp3" data-audio-us-female="/audios/us/Do-all-us-female.mp3"></span>
-> - *Do it* - <span class="pho alt">ˈduː ˈɪt</span> ⭢ <span class="pho alt">ˈduːʷɪt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Do-it-us-male.mp3" data-audio-us-female="/audios/us/Do-it-us-female.mp3"></span>
-> - *Throw it* - <span class="pho alt">ˈθroʊ ˈɪt</span> ⭢ <span class="pho alt">ˈθroʊʷɪt</span><span class="speak-word-inline" data-audio-us-male="/audios/us/Throw-it-us-male.mp3" data-audio-us-female="/audios/us/Throw-it-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/2.5-prosody.md b/1000-hours/sounds-of-american-english-old/2.5-prosody.md
deleted file mode 100644
index d1bf0937..00000000
--- a/1000-hours/sounds-of-american-english-old/2.5-prosody.md
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@@ -1,30 +0,0 @@
-# 2.5. 韵律（Prosody）
-
-学说话，其实就是低配版的学唱歌。这个类比的好处在于，它让我们把日常连贯的语音理解成一串音节，而不是一些放在一起的单词（一个单词可能有一个以上的音节）—— 因为自然语音，本质上都是以音节为基础单位，而不是以字词为单位的……
-
-Learning to speak is, in many ways, a simpler version of learning to sing. This comparison is useful because it allows us to perceive everyday, fluid speech as a string of syllables, not just a group of words (a single word can have more than one syllable). After all, natural speech is fundamentally based on syllables, not words.
-
-歌曲是有韵律的，自然语音其实也一模一样…… 好听的歌声和好听的语音，简单说，总计需要注意以下几个方面：
-
-The prosody of speech is like the rhythm of a song. To make our speech or singing appealing to the ear, there are a few key elements we need to pay attention to. These are:
-
-> **高低**、**起伏**、**轻重**、**缓急**…… 以及，很多人并不重视的**停顿**（[2.4.1](2.4.1-stop)）。
->
-> *pitch*, *tone*, *emphasis*, *rhythm*, and oft-neglected *pauses*([2.4.1](2.4.1-stop)).
->
-> * **高低**指的是**音高**（*pitch*）的变化。
-> * *Pitch* refers to the high and low variations in voice.
-> * **起伏**指的是**声调**（*tone*），即，扬、平、降、轻。
-> * *tone* refers to the tone of voice, whether it's *rising*, *flat*, *falling*, or *light*.
-> * **轻重**（*stress*）落实到**音节**（就好像歌曲中的**音符**）上来看，就是轻重的安排，重音、次重音、非重音、弱音（[2.3.2](2.3.2-stress)）。
-> * *Stress* refers to the emphasis placed on a syllable, similar to the emphasis on a note in a song. There are various levels of stress such as *primary stress*, *secondary stress*, *unstressed*, and *weak schwa* ([2.3.2](2.3.2-stress)).
-> * **缓急**（*rhythm*）由一组**音节**发声的速度构成 —— 在歌曲中，如果 4 个音符在同一个节拍里唱完，每个音符只占 $\frac{1}{4}$ 拍，那就每个音节都**很短**且**很快**；或者反过来，如果一个音符竟然持续了 2 个节拍，那就是这个音节**很长**，但**很慢**。
-> * *rhythm* is the speed at which a group of syllables is spoken. In a song, if four notes are sung in one beat, each note lasts a quarter of a beat, making each syllable short and fast. Conversely, if a single note spans two beats, the syllable is long and slow.
-
-所以，**好好说话**，**说得连贯**，甚至**说得好听**，更重要的是**学会如何安排好每一个音节**，而所谓的 “安排好”，就是处理**高低、起伏、轻重、缓急**以及**停顿**。
-
-Therefore, to speak well, to speak fluently, even to speak beautifully, we need to learn how to properly arrange each syllable, handling its *pitch*, *tone*, *stress*, *rhythm*, and *stop* or *pauses*.
-
-虽然**把每个音素读准读对**看起来更基础，但实际上更重要的是每个音节的**韵律**，即，该**音节**的**高低、起伏、轻重、缓急**，比这个还重要的，是很多人没想到的**音节间**可能的**停顿**。
-
-While it might seem more basic to pronounce each phoneme correctly, what's actually more crucial is the prosody of each syllable, including the *pitch*, *variation*, *stress*, and *rhythm* of the syllable, and what's even more important is the potential *stop* or *pause* between syllables, which is something many people overlook.
diff --git a/1000-hours/sounds-of-american-english-old/2.5.1-pitch.md b/1000-hours/sounds-of-american-english-old/2.5.1-pitch.md
deleted file mode 100644
index 981aa2db..00000000
--- a/1000-hours/sounds-of-american-english-old/2.5.1-pitch.md
+++ /dev/null
@@ -1,39 +0,0 @@
-# 2.5.1 高低（Pitch）
-
-被清楚地读出的音节，有可能伴随着高低不同的音高（*Pitch*）变化。
-
-Clear syllables when pronounced, may vary in *pitch*.
-
-> **Yet**, | it is a fact of **life** | that an unlettered **pea**sant is considered **ig**norant.
-
-这句话里，*Yet* 和 *life* 这两个单音节词汇，以及 *peasant* 的第一个音节 <span class="pho alt">pe</span>，以及 *ignorant* 里的第一个音节 <span class="pho alt">ɪg</span>，都有明显的音高（*pitch*）拉升。语音分析工具可以帮我们清楚地 “看到”：
-
-In this sentence, the single syllable words *Yet* and *life*, the first syllable <span class="pho alt">pe</span> in *peasant*, and <span class="pho alt">ɪg</span> in *ignorant*, all experience a noticeable *pitch lift*. Voice analyzing software can help us *see* this clearly:
-
-<video controls width="720"> <source src="/videos/yet-it-is-a-fact-of-life.mp4" type="video/mp4"></source>Your browser does not support the video tag. </video>
-
-以上视频来自于 2023 年 9 月我自己写的第一个 Demo（[ToBI Player](https://github.com/xiaolai/tobiplayer)）—— 现在的 [Enjoy App](https://1000h.org/enjoy-app/) 就是从它开始后继组织人员开发的。在 Enjoy App 中，你同样可以看到每句话的音频波谱（waveform）以及高低（音高）起伏（声调，即[下一章](2.5.2-tone)的讲解）……
-
-The video above is from a demo I wrote myself in September 2023 ([ToBI Player](https://github.com/xiaolai/tobiplayer)). This demo eventually led to the development of the current [Enjoy App](https://1000h.org/enjoy-app/) with a team. In the Enjoy App, you can also see the waveform of each sentence and its pitch fluctuations (intonation, which will be explained in [the next chapter](2.5.2-tone))...
-
-如果你可以唱出 $\frac{4}{4}$ <span class="pho">| 3 2 1 - |</span> —— 当然，这三个音符其实任何人都可以唱出来……
-
-If you can sing $\frac{4}{4}$ | 3 2 1 - | - indeed, anyone could sing these three notes...
-
-<video controls width="720"> <source src="/videos/321.mp4" type="video/mp4"></source>Your browser does not support the video tag. </video>
-
-那你就可以把 *fact*, *fact*, *fact*... 用三个不同的音唱出来，<span class="pho">/fækt/(3) /fækt/(2) /fækt/(1-)</span>，你就能体会到自然语音中的**音高**变化了。
-
-Then you can voice *fact*, *fact*, *fact*... in three different pitches, <span class="pho">/fækt/(3) /fækt/(2) /fækt/(1-)</span>, and you will then feel the *pitch* changes in natural speech.
-
-**音高**（*pitch*）的控制，主要靠**喉部**（*larynx*）；而**声调**（*tone*, [2.5.2](2.5.2-tone)），由于涉及到音高的变化（**从高到低**或者**从低到高**），所以，也由喉部控制。如果有个人在我们面前讲话，在我们听到她声调明显变化的时候，就可以看得到她的喉咙部位的明显动作……[^1]
-
-Pitch control mainly relies on the *larynx*. *tone* ([2.5.2](2.5.2-tone)), which involves pitch variation (from high to low or from low to high), is also controlled by the *larynx*. If someone is speaking in front of us, we can see the clear movement in their throat when we hear a noticeable change in their pitch...[^1]
-
-<video controls width="720"> <source src="/videos/CatherineAnderson.mp4" type="video/mp4"></source>Your browser does not support the video tag. </video>
-
-之所以 “说话” 只不过是 “极其低配版的歌唱”，是因为它的曲调（*Melody*）只是在一个特别狭小音高区域（*Pitch range*）里变化。
-
-The reason why *speaking* can be considered as *extremely pared-down singing* is because its melody (prosody) only fluctuates within a very narrow pitch range.
-
-[^1]: The video clip came from *[Essentials of Linguistics, 2nd edition](https://ecampusontario.pressbooks.pub/essentialsoflinguistics2/)*，and the narrator is one of the authors, Catherine Anderson。
diff --git a/1000-hours/sounds-of-american-english-old/2.5.2-tone.md b/1000-hours/sounds-of-american-english-old/2.5.2-tone.md
deleted file mode 100644
index 4829f21c..00000000
--- a/1000-hours/sounds-of-american-english-old/2.5.2-tone.md
+++ /dev/null
@@ -1,75 +0,0 @@
-# 2.5.2. 起伏（Tone）
-
-把中文当作外语学习的时候，最麻烦的一件事是学习中文每个字的声调，一二三四声以及轻声。<span class="pho">ma</span> 这个音，可以有 <span class="pho">mā, má, mǎ, mà</span> 以及 <span class="pho">ma</span>。更令人格外头痛的是：同一个音的不同声调会代表不同的含义。
-
-When learning Chinese as a foreign language, one of the biggest hurdles is mastering the *tones* of each character. For example, the sound <span class="pho">ma</span> can be expressed as <span class="pho">mā, má, mǎ, mà</span> or with a *soft tone* <span class="pho">ma</span>, each with a different meaning depending on the tone.
-
-英文的音节不仅没有指定的声调，并且，声调的变化也不影响音节的含义。一般来说，声调主要在**重音音节**上有所体现。偶尔，在**句末**或者**意群末**的最后一个**非重音音节**也可能带着声调 —— 这时一般只有**平调**。
-
-In contrast, English syllables don't have designated tones, and changes in tone won't alter the meaning of the syllable. Tones in English are usually reflected on the stressed syllable. Sometimes, the last unstressed syllable at the end of a sentence or phrase may carry a tone, which is typically a flat tone.
-
-理论上，**重音音节**都可以有最常见的三种声调的读法，**平调**、**升调**、**降调**。比如，<span class="pho">→</span>*big*, <span class="pho">↗</span>*big*, <span class="pho">↘</span>*big*，<span class="pho">→</span>*fact*, <span class="pho">↗</span>*fact*, <span class="pho">↘</span>*fact*…… 而**非重音音节**只有**轻声**。
-
-In theory, *stressed syllables* can have the three most common tones: *flat*, *rising*, or *falling*. You could say *big* with a flat, rising, or falling tone, <span class="pho">→</span>*big*, <span class="pho">↗</span>*big*, <span class="pho">↘</span>*big*; the same goes for *fact*, <span class="pho">→</span>*fact*, <span class="pho">↗</span>*fact*, <span class="pho">↘</span>*fact*... In contrast to stressed syllables, *unstressed syllables* are *always* pronounced in a *soft tone*.
-
-偶尔，你也会听到一些人会使用**降升调**，一般是在**双元音**上。比如，<span class="pho">⤻</span>sure, i<span class="pho">⤻</span>dea…… 更多的时候，**降升调**实际上是由两个音节构成的，前一个音节降调，后一个音节升调，比如，*progress* 可以被读成 <span class="pho">↘</span>*pro*<span class="pho">↗</span>*gress*.
-
-Occasionally, a *falling-rising* tone is used, typically on *diphthongs*, for instance, *<span class="pho">⤻</span>sure* or *i<span class="pho">⤻</span>dea*. More often than not, a *falling-rising* tone is actually made up of two syllables, with the first syllable falling and the second syllable rising. For instance, the word *progress* can be pronounced as <span class="pho">↘</span>*pro*<span class="pho">↗</span>*gress*
-
-注意：如果**短元音**的音节用**平调**读出来，会自然而然地有所**拉长**。
-
-Note: *Short vowel* syllables read with a *flat* tone naturally tend to *lengthen*.
-
-如果是多音节词汇，要分两种情况：
-
-For multi-syllable words, there are two scenarios:
-
-> * 最后一个音节是**重音**：*adapt*, a<span class="pho">→</span>dapt，a<span class="pho">↗</span>dapt，a<span class="pho">↘</span>dapt
->
-> * Last syllable is stressed: *adapt*, a<span class="pho">→</span>dapt，a<span class="pho">↗</span>dapt，a<span class="pho">↘</span>dapt
->
-> * 倒数第二个音节是重音：
->
-> * Penultimate syllable is stressed:
->
->   * 第一种情况是**重音**用更高**音调** —— 以下用 <span class="pho">↑</span> 表示音调（*pitch*）的提高：
->
->   * First case: using *a higher pitch* for the stressed syllable, indicated by <span class="pho">↑</span> for pitch increase:
->
->     * *component*, com<span class="pho">↑</span>po·nent
->
->     * *condition*, con<span class="pho">↑</span>di·tion
->
->       在这种情况下，最后一个音节只能继续**轻声**读出来……
->
->       In this case, the last syllable should continue to be read in a *soft tone*.
->
->   * 第二种情况是**重音**用**降调**
->
->   * Second case: using a falling tone for the stressed syllable:
->
->     * *component*, com<span class="pho">↘</span>po<span class="pho">→</span>nent，com<span class="pho">↘</span>po<span class="pho">↗</span>nent，com<span class="pho">↘</span>po·nent
->
->     * *condition*, con<span class="pho">↘</span>di<span class="pho">→</span>tion，con<span class="pho">↘</span>di<span class="pho">↗</span>tion，con<span class="pho">↘</span>di·tion
->
->       由于倒数第二个音节是**重音**，声调在那里已经明显**完成**，所以，随后的最后一个音节只需要**轻声**读出来就可以了。
->
->       Since the penultimate syllable is *stressed* and the tone is clearly *completed* there, the last syllable only needs to be read *softly*.
-
-含有重音的多音节单词读的时候就是相对更为吃力。在日常对话中，人们为了方便会下意识地尽量避免使用多音节单词。在口语中更多且又自然地使用含有重音的多音节单词，多多少少是多年教育的结果 —— 在学校里朗读背诵了更多的内容。
-
-Pronouncing multi-syllable words with stress is more challenging. In casual conversation, people tend to avoid using multi-syllable words. The more frequent and natural use of multi-syllable words with stress in spoken English is largely the result of years of education — spending more time reading and reciting content in school.
-
-> [!Tip]
-> 这是很多人学英语从未养成的习惯：
-> > 在学一个新的英语词汇的时候，要分别用几个声调各自读很多遍……
->
-> One habit many English learners haven't developed is to *practice a new vocabulary word with different tones repeatedly*.
-
-传统的语音教学里，**声调**（*intonation*）一般只涉及到句末的词汇，疑问句用**升调**，祈使句用**降调** —— 到此为止。
-
-Traditional phonetics lessons usually only cover *intonation* at the ends of sentences, with *rising* tones for questions and *falling* tones for commands.
-
-事实上，自然语流中，**每个非弱读音节都可能有属于自己的声调** —— 只不过，在没有计算机辅助的情况下，哪怕是母语使用者也无法逐一分辨…… 事实上，很多人连自己语音的每个音节声调究竟是如何控制的都无法说清楚。
-
-However, in natural speech, every non-weak syllable might carry its own tone. Without technological assistance, even native speakers might struggle to distinguish these subtle differences. In fact, many people can't articulate how they control the tone of each syllable in their own speech.
\ No newline at end of file
diff --git a/1000-hours/sounds-of-american-english-old/2.5.3-emphasis.md b/1000-hours/sounds-of-american-english-old/2.5.3-emphasis.md
deleted file mode 100644
index dc07e812..00000000
--- a/1000-hours/sounds-of-american-english-old/2.5.3-emphasis.md
+++ /dev/null
@@ -1,166 +0,0 @@
-# 2.5. 轻重（Emphasis）
-
-自然语音中，不可能每个词汇都被用同样轻重的方式读出来 —— 总是有些词被**强调**，而另外一些词读的相对较轻。
-
-In natural speech, not every word is pronounced with the same *emphasis*. Some words are *stressed* or *highlighted*, while others are read in a lighter, less emphasized manner.
-
-不妨体会以下**同一个句子**的 4 个版本（例子来自于 [Macquarie University](https://www.mq.edu.au/about/about-the-university/our-faculties/medicine-and-health-sciences/departments-and-centres/department-of-linguistics/our-research/phonetics-and-phonology/speech/phonetics-and-phonology/Intonation-tobi-introduction)）：
-
-Consider the following 4 versions of the same sentence (examples from [Macquarie University](https://www.mq.edu.au/about/about-the-university/our-faculties/medicine-and-health-sciences/departments-and-centres/department-of-linguistics/our-research/phonetics-and-phonology/speech/phonetics-and-phonology/Intonation-tobi-introduction)):
-
-> *Marianna made the marmalade...*
->
-> 1. <audio controls><source src="/audios/marm1.wav" type="audio/mpeg">Your browser does not support the audio element.</source></audio>
->
-> 2. <audio controls><source src="/audios/marm2.wav" type="audio/mpeg">Your browser does not support the audio element.</source></audio>
->
-> 3. <audio controls><source src="/audios/marm3.wav" type="audio/mpeg">Your browser does not support the audio element.</source></audio>
->
-> 4. <audio controls><source src="/audios/marm4.wav" type="audio/mpeg">Your browser does not support the audio element.</source></audio>
-
-拿第 1 个版本为例，请参照以下图示：
-
-In the first version, for example, please refer to the following diagram:
-
-![nuclear-accented-words](/images/nuclear-accented-words.svg)
-
-同样一个句子，**强调**不同的**词**可能表达不同的含义[^1]：
-
-The same sentence, by *emphasizing* different *words*, can convey different meanings[^1].
-
-> * Will **you** drive to the office tommorrow? (rather than someone else)
-> * Will you **drive** to the office tommorrow? (rather than going some other way)
-> * Will you drive **to** the office tommorrow? (rather than from the office)
-> * Will you drive to the **office** tommorrow? (rather than somewhere else)
-> * Will you drive to the office **tommorrow**? (rather than some other day)
-
-被**强读**的词汇之中，重音音节往往带着**声调** —— 升、降、平、降升（[2.5.2](2.5.2-tone)）。并且，少数重音音节会有被拔高的音高（[2.5.1](2.5.1-pitch)）。这些都是自然语流的韵律（*prosody*）格外重要的组成部分，也是跟读模仿时的重点之一。
-
-Stressed words often carry *tone* ([2.5.2](2.5.2-tone)) - *rising*, *falling*, *flat*, or *falling-rising*. Moreover, a few stressed syllables might have a higher *pitch*. These are significant parts of natural speech  *prosody*, and should be a focus when imitation reading.
-
-另外，除了少数词汇会被**强读** 之外，还会有很多词汇会被**弱读**。
-
-In addition, besides a few words being *stressed*, many words will be *weakly pronounced.*
-
-以下是某段 TOEFL 听力录音中前两个句子，请注意同一个单词 “**community**” 第一次出现和第二次出现时的具体不同：
-
-Here are two sentences from the TOEFL listening recording. Note the specific difference when the word *community* appears for the first and second time:
-
-> *Community* service is an important component of education here at our university. We encourage all students to volunteer for at least one *community* activity before they graduate.
-
-<audio controls><source src="/audios/toefl-sampe-01.mp3" type="audio/mpeg">Your browser does not support the audio element.</source></audio>
-
-这段录音中所有被强读的词汇在以下的文本中被加重标记（而没有标记的，就是被弱读的）：
-
-In this recording, all the words that are *stressed* are highlighted in the following text (those not marked are weakly pronounced):
-
-> **Community** **service** is an **important** **component** of **education** **here** at our **university**. We **encourage** **all** **students** to **volunteer** for at **least** **one** community **activity** **before** they **graduate**.
-
-自然语音中，会有大量的常见词汇会被**弱读** —— 尤其是那些最常见的单音节词汇。
-
-In natural speech, a large number of common words are weakly pronounced - especially those most common single syllable words.
-
-各种语言都有这种现象，主要原因可能是因为**太常见**、**太容易理解**、**不可能被误解**、**相对于不那么重要**等等诸如此类的原因，乃至于说话者在说那些**词汇**（或者**音节**）的时候会**更快**或者**更轻**，甚至**合并**或者**省略**。
-
-This phenomenon exists in all kinds of languages. The main reason might be because these words are too common, too easily understood, cannot be misunderstood, relatively unimportant, and so on. As a result, when speakers say these words (or syllables), they tend to speak faster or lighter, even merging or omitting them.
-
-北京人在说 “不知道” 这三个字的时候，有可能说出来的是用拼音都很难标记的 <span class="pho">bù(r)dào</span>，其中原本应该的 <span class="pho">zhī</span> 被糊弄成了甚至好像没有韵母的 <span class="pho">r</span>…… 但，谁都听得懂，哪怕最初不习惯，听个两三次也就适应了。
-
-For example, when Beijingers say "不知道", it might come out as <span class="pho">bù(r)dào</span>, where the original <span class="pho">zhī</span> is mumbled into an <span class="pho">r</span> that doesn't even seem to have a vowel. But everyone understands it, and even if you're not used to it at first, you'll adapt after hearing it a few times.
-
-某个单词被强读或者被弱读的时候，该单词的元音长短和重音所在（如果是多音节单词的话）都会相应发生变化，具体常见变化如下：
-
-When a word is stressed or weakly pronounced, the length of the vowels and the location of the stress (if it's a multisyllabic word) will change accordingly. The common changes are as follows:
-
-如果一个音节是重音或被**强读**，那么这个单词中的：
-
-If a syllable is *stressed*, or *emphasized*:
-
-> * 长元音会被读的很清楚，并且足够长，甚至显得更长一些；
-> * Long vowels are pronounced very clearly and long enough, even a bit longer;
-> * 双元音会被读的很饱满，并且显得很有弹性；
-> * Diphthongs are pronounced full and elastic;
-> * 落在重音上的短元音都会显得更长一些；
-> * Short vowels on the stressed syllables appear longer;
-> * 重音所在的音节可能带着不同的声调（平调、升调、降调、降升）……
-> * The syllable with the stress might carry different tone (flat, rising, falling, falling-rising);
-> * 重音所在的音节可能带着更高的音高（往往是 “高”、“中”、“低” 中的 “高”）……
-> * The syllable with the stress might often carry a *higher pitch*, often *high* among *high*, *middle*, *low*.
-
-如果一个音节被**弱读**，那么这个单词中的：
-
-If a syllable is *weakly pronounced*:
-
-> * 长元音会变得短一些（几乎与短元音的长度相当）；
-> * Long vowels can get shorter (almost as short as short vowels);
-> * 重音音节会变得与非重音音节一样轻；
-> * The stressed syllable can be as light as the unstressed syllable;
-> * 很多元音都会发生变化，向 *schwa* <span class="pho">ə</span>（[2.1.3](2.1.3-ʌ)、[2.1.5](2.1.5-ə)）靠拢；
-> * Many vowels might change, moving towards *schwa* <span class="pho">ə</span> ([2.1.3](2.1.3-ʌ)、[2.1.5](2.1.5-ə));
-> * 很多与辅音相关的停顿（[2.4.1](2.4.1-stop), [2.4.3.1](2.4.3-cc#_2-4-3-1-省音-elision)）会被直接省略；
-> * Many stops or pauses ([2.4.1](2.4.1-stop), [2.4.3.1](2.4.3-cc#_2-4-3-1-省音-elision)) related to consonants can be directly omitted;
-> * 清辅音 <span class="pho">s</span>、<span class="pho">t</span>、<span class="pho">k</span>、<span class="pho">f</span> 之后的元音 <span class="pho">ə</span> 可能会直接被省略掉；
-> * The vowel <span class="pho">ə</span> after <span class="pho">s</span>, <span class="pho">t</span>, <span class="pho">k</span>, <span class="pho">f</span> might be directly omitted;
-> * 整个单词所处的音高往往是 “高”、“中”、“低” 之中的 “低”，最多是 “中”……
-> * The whole word often has a *lower* pitch,  or at most *middle* pitch among *high*, *middle*, *low*.
-
-其实，哪怕在单独读某一个单词的时候，其中元音的长短都会受到重音重读的影响。比如，*city* 这个单词，重音在第一个音节上，而两处的元音是一样的：<span class="pho alt">ˈsɪ-t̬ɪ</span>；但是只要你把第一个音节读得足够重，自然而然就能感觉到**第一个音节**只能比**第二个音节**更长（[2.3.2](2.3.2-stress)）。
-
-Actually, even when pronouncing a single word, the length of the vowels is influenced by the stress. For example, in the word *city*, the stress is on the first syllable, and both vowels are the same: <span class="pho alt">ˈsɪ-t̬ɪ</span>. But if you pronounce the first syllable heavy enough, you will naturally feel that the first syllable can only be longer than the second one ([2.3.2](2.3.2-stress)).
-
-大多数助动词、系动词、介词、连词、冠词、代词，都有两种发音形式：**强读式**（*accented form*）、**弱读式**（*weak form*） —— 这些单词往往都是单音节单词。在自然语流中，它们更多的情况下是以**弱读式**读出的。以下是其中最常见的强读式、弱读式对照列表。注意，以下的列表不能当作硬规则使用，不是所有的虚词都必须被弱读；也不是所有的实词都必须被强读。下面的列表只是在描述现象。
-
-Most *auxiliary verbs*, *linking verbs*, *prepositions*, *conjunctions*, *articles*, and *pronouns* have two pronunciation forms: *accented form* and *weak form* - these words are often single syllable words. In natural speech, they are more often pronounced in the weak form. Below is a list of the most common accented and weak forms. Note, the list below cannot be used as hard rules. Not all function words must be weakly pronounced; not all content words must be stressed. The list below is only describing the phenomenon.
-
-> * a: <span class="pho alt">eɪ</span> → <span class="pho alt">ə</span>
-> * am: <span class="pho alt">æm</span> → <span class="pho alt">əm, m</span>
-> * an: <span class="pho alt">æn</span> → <span class="pho alt">ən, n</span>
-> * and: <span class="pho alt">ænd</span> → <span class="pho alt">ənd, nd, ən, n</span>
-> * any: <span class="pho alt">'eni</span> → <span class="pho alt">ni</span>
-> * are: <span class="pho">/ɑ/:</span> → <span class="pho alt">ə</span>
-> * as: <span class="pho alt">æs</span> → <span class="pho alt">əz</span>
-> * at: <span class="pho alt">æt</span> → <span class="pho alt">ət</span>
-> * but: <span class="pho alt">bʌt</span> → <span class="pho alt">bət</span>
-> * can: <span class="pho alt">kæn</span> → <span class="pho alt">kən, kn, kŋ</span>
-> * could: <span class="pho alt">kud</span> → <span class="pho alt">kəd, kd</span>
-> * do: <span class="pho alt">duː</span> → <span class="pho alt">du, də, d</span>
-> * does: <span class="pho alt">dʌz</span> → <span class="pho alt">dəz</span>
-> * for: <span class="pho alt">fɔː</span> → <span class="pho alt">fə, f</span>
-> * from: <span class="pho alt">frɔm</span> → <span class="pho alt">frəm, frm</span>
-> * had: <span class="pho alt">hæd</span> → <span class="pho alt">həd, əd, d</span>
-> * has: <span class="pho alt">hæz</span> → <span class="pho alt">həz, əz</span>
-> * have: <span class="pho alt">hæv</span> → <span class="pho alt">həv, həf, əv, əf</span>
-> * he: <span class="pho alt">hiː</span> → <span class="pho alt">hi, iː, i</span>
-> * her: <span class="pho alt">həː</span> → <span class="pho alt">hə, əː, ə</span>
-> * him: <span class="pho alt">him</span> → <span class="pho alt">im</span>
-> * his: <span class="pho alt">hiz</span> → <span class="pho alt">iz</span>
-> * I: <span class="pho alt">ai</span> → <span class="pho alt">aː, ə</span>
-> * is: <span class="pho alt">iz</span> → <span class="pho alt">s, z</span>
-> * many: <span class="pho alt">'meni</span> → <span class="pho alt">mni</span>
-> * me: <span class="pho alt">miː</span> → <span class="pho alt">mi</span>
-> * must: <span class="pho alt">mʌst</span> → <span class="pho alt">məst, məs</span>
-> * my: <span class="pho alt">mai</span> → <span class="pho alt">mi</span>
-> * of: <span class="pho alt">əv</span> → <span class="pho alt">əv, v, f, ə</span>
-> * our: <span class="pho alt">ɑʊɚ</span> → <span class="pho">/ɑr</span> ⭢ <span class="pho">ɑ/</span>
-> * shall: <span class="pho alt">ʃæl</span> → <span class="pho alt">ʃəl, ʃl</span>
-> * she: <span class="pho alt">ʃiː</span> → <span class="pho alt">ʃi</span>
-> * should: <span class="pho alt">ʃud</span> → <span class="pho alt">ʃəd, ʃd, ʃt</span>
-> * so: <span class="pho alt">səʊ</span> → <span class="pho alt">sə</span>
-> * some: <span class="pho alt">sʌm</span> → <span class="pho alt">səm, sm</span>
-> * such: <span class="pho alt">sʌʧ</span> → <span class="pho alt">səʧ</span>
-> * than: <span class="pho alt">ðæn</span> → <span class="pho alt">ðən, ðn</span>
-> * that: <span class="pho alt">ðæt</span> → <span class="pho alt">ðət</span>
-> * the: <span class="pho">/ði/:</span> → <span class="pho alt">ði, ðə</span>
-> * them: <span class="pho alt">ðem</span> → <span class="pho alt">ðəm, ðm, əm, m</span>
-> * then: <span class="pho alt">ðen</span> → <span class="pho alt">ðən</span>
-> * to: <span class="pho alt">tuː</span> → <span class="pho alt">tu, tə, t</span>
-> * us: <span class="pho alt">us</span> → <span class="pho alt">əs</span>
-> * was: <span class="pho alt">wɔz</span> → <span class="pho alt">wəz, wə</span>
-> * we: <span class="pho alt">wiː</span> → <span class="pho alt">wi</span>
-> * were: <span class="pho alt">wəː</span> → <span class="pho alt">wə</span>
-> * when: <span class="pho alt">wen</span> → <span class="pho alt">wən</span>
-> * will: <span class="pho alt">wɪl</span> → <span class="pho">/əl, l</span>/
-> * would: <span class="pho alt">wuːd</span> → <span class="pho alt">wəd, əd</span>
-> * you: <span class="pho alt">juː</span> → <span class="pho alt">ju, jə</span>
-
-[^1]: This example came from *Manual of American English Pronunciation*, 4th edition, by Clifford H. Prator, Jr. BettyWallaceRobinett, 1972
\ No newline at end of file
diff --git a/1000-hours/sounds-of-american-english-old/2.5.4-pace.md b/1000-hours/sounds-of-american-english-old/2.5.4-pace.md
deleted file mode 100644
index d70aa00f..00000000
--- a/1000-hours/sounds-of-american-english-old/2.5.4-pace.md
+++ /dev/null
@@ -1,46 +0,0 @@
-# 2.5.4. 缓急（Pace）
-
-自然语音中，被强读的音节通常语速较慢，伴随着音高的变化、声调的不同，并且，其中的长元音读得够长，双元音读得够饱满。
-
-In natural speech, syllables that are emphasized tend to be spoken more slowly. They are often associated with changes in pitch, different tones, and the elongation of long vowels and diphthongs.
-
-与之相对的，另外一些音节会被轻读，它们常常会很轻很快，弄不好还会有大量的变音。
-
-In contrast, some syllables are pronounced more weakly. They are frequently very soft and quick, and if not done correctly, may have many variations in pronunciation.
-
-还是以这句话为例子：
-
-Let's still use this sentence as an example:
-
-> Community service is an important component of education *here at our uni*·**ver**·*sity*. We encourage all students to volunteer for at least one community activity before they graduate.
-
-<audio controls><source src="/audios/toefl-sampe-01.mp3" type="audio/mpeg">Your browser does not support the audio element.</source></audio>
-
-请仔细注意这一串音节：*here at our uni*·**ver**·*sity*... 它们原本应该被读作  <span class="pho alt">ˈhiə æt ɑʊə ˌjunəˈvəː(r)səti</span>…… 可你听到的是什么呢？<span class="pho">ˈ/hiə·(æ)t̬ɑ(ʊə)ˌjunə·ˈvəː(r)sət̬i/</span>（括号里的音素省略到几乎听不清）……
-
-Pay close attention to this string of syllables: *here at our uni*·**ver**·*sity*... They're supposed to be pronounced as <span class="pho alt">ˈhiə æt ɑʊə ˌjunəˈvəːsəti</span>, but what do you hear instead? <span class="pho">ˈ/hiə·(æ)t̬ɑ(ʊə)ˌjunə·ˈvəː(r)sət̬i/</span> (with vowel sounds in parentheses being nearly omitted)...
-
-> * *at* 被轻读成 <span class="pho alt">ət</span>，而其中的 <span class="pho">ə</span> 又几乎被省略掉了；
-> * *at* is de-emphasized to <span class="pho alt">ət</span> with the <span class="pho">ə</span> almost left out;
-> * 而 *our* 原本单独朗读的话，应该是 <span class="pho alt">ɑʊə</span>，却只变成了 <span class="pho alt">ɑ</span>；又由于这是美式发音（毕竟是 TOEFL 听力考试题），好像是多了个 <span class="pho">r</span>，所以是 <span class="pho alt">ɑr</span>；
-> * *our*, when pronounced alone, should be <span class="pho alt">ɑʊə</span>, but is reduced to <span class="pho alt">ɑ</span> or <span class="pho alt">ɑr</span> due to American pronunciation adding an <span class="pho">r</span>;
-> * *at* 中的 <span class="pho">t</span>，由于前后被两个元音夹着，所以变成了和 <span class="pho">d</span> 非常接近的 <span class="pho">t̬</span>；
-> * The <span class="pho">t</span> in *at*, sandwiched between two vowels, is pronounced similarly to <span class="pho">d</span>, becoming <span class="pho">t̬</span>;
-> * 为了把 *university* 中的长元音重读音节 <span class="pho alt">vəː</span> 读清楚，与前一个音节 <span class="pho alt">junə</span> 之间有个细微的停顿，而  <span class="pho alt">vəː</span>  读成了平调……
-> * To emphasize the stressed syllable <span class="pho alt">vəː</span> in *university*, there's a slight pause between it and the preceding syllable <span class="pho alt">junə</span>, and <span class="pho alt">vəː</span> is pronounced with a flat tone.
-
-关键在于，好听的语音是有节奏感的。该朗读者把 <span class="pho">ˈ/hiə·(æ)t̬ɑ(ʊə)ˌjunə</span> 放进了同一个节拍里，然后，下一个节拍从重音 <span class="pho">ˈvəː</span> 开始：<span class="pho">ˈ/hiə·(æ)t̬ɑ(ʊə)ˌjunə | ˈvəː(r)sət̬i/</span>……
-
-The key point is that attractive speech has *pace*. The speaker put <span class="pho">ˈ/hiə·(æ)t̬ɑ(ʊə)ˌjunə</span> into one beat, then started the next beat with the stressed syllable <span class="pho">ˈvəː</span>: <span class="pho">ˈ/hiə·(æ)t̬ɑ(ʊə)ˌjunə | ˈvəː(r)sət̬i/</span>...
-
-日常生活中，绝大多数人讲话并不会刻意在乎**节奏**，也常常感觉并无必要。但，总有一些人是训练有素的，比如，他们需要朗读、录音、演讲，甚至表演…… 于是，他们会有意无意地控制**节奏**。
-
-In everyday life, most people don't consciously pay attention to *pace* when speaking, nor do they feel the need to. But some people have trained to precisely control their *pace* when reading aloud, recording, giving speeches, or performing.
-
-这也是为什么绝大多数人在模仿外语录音的时候总是感觉心有余力不足的原因，首先因为他们忽视了**节奏**这个格外重要的因素。另外，他们忘了被模仿的语音，是训练有素且相当专业的声音，那甚至是质量极高难度极大的表演 —— 这更是提高了普通人模仿的难度。
-
-This is why most people find it challenging to imitate foreign language recordings accurately. First, they overlook the essential factor of *pace*. Plus, they forget that the speech they're trying to mimic is a professionally trained and high-quality performance, which raises the difficulty level of imitation.
-
-然而，说话的**节奏**，本质上来看，毕竟没多复杂，只不过是由**长短**和适当**停顿**构成的…… 再加上**高低起伏轻重**构成的**韵律**，就更好听了。
-
-However, the *rhythm* of speech isn't overly complex. It's essentially determined by the *length* of sounds and appropriate *stops* or  *pauses*... Add in the *prosody* created by variations in *pitch* and *stress*, and the speech becomes even more pleasant to the ear.
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-# 3. 收官（Wrapping up）
-
-最后，还有一些需要注意的地方，可能更为重要 —— 其障碍竟然往往来自主观感受，而非客观事实。
-
-Finally, there's something more crucial to keep in mind - the obstacles we face often stem from our own subjective perceptions, rather than objective facts.
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-# 3.1 流利（Fluency）
-
-学习另外一种语言，总是要处理很多与母语**不一样**的细节。
-
-Learning another language always involves navigating a myriad of details that differ from native tongue.
-
-> **凡是和母语发声方式不一样的地方，都是语音塑造的重点**。
->
-> **Any differences in pronunciation from your native language should be the focus of speech training**.
-
-在语音中，最重要且最普遍被忽视的**差异**是：
-
-One of the most important and often overlooked *differences* is:
-
-> 英文的**音节**在**绝大多数情况下**读出来都比亚洲语言的**字**要**长**许多……
->
-> English syllables, in most cases, are pronounced *much longer* than the individual characters in Asian languages...
-
-首先，英文的元音有长短之分，除了 *6* 个基础元音 <span class="pho">ʌ</span>、<span class="pho">e</span>、<span class="pho">ə</span>、<span class="pho">ɪ</span>、<span class="pho">ʊ</span>、<span class="pho">ɒ</span> 是短元音之外，剩下的十几个都是**相对更长**的元音；而亚洲语言的元音都是等长的。
-
-Firstly, English vowels have variations in length. Aside from the *6* basic short vowels <span class="pho">ʌ</span>, <span class="pho">e</span>, <span class="pho">ə</span>, <span class="pho">ɪ</span>, <span class="pho">ʊ</span>, and <span class="pho">ɒ</span>, the remaining more than dozen vowels are relatively longer. In contrast, vowels in Asian languages are all of equal length.
-
-除此之外，在英文中，当一个短元音处于重音音节的时候，会出现因强调而发生的短元音变长的情况。比如，你可以试着说一下 *This is a **big** **city**!* —— 为了强调 *big*，你会不由自主地将它读成长长的 <span class="pho alt">biːg</span>，而不是 <span class="pho alt">bɪg</span>，如果强调 *city*，它的第一个 <span class="pho alt">sɪ</span> 也会稍微变长一点点（你可以把 <span class="pho">s</span> 拉长）……
-
-In English, a short vowel in a stressed syllable can *elongate* when emphasized. For example, try saying, *This is a **big** **city**!* You'll notice that to emphasize *big*, you naturally stretch it into a long-sounding <span class="pho alt">biːg</span>, instead of the short <span class="pho alt">bɪg</span>. If you stress *city*, the first <span class="pho alt">sɪ</span> will also lengthen slightly - you can stretch the <span class="pho">s</span> sound.
-
-而英文的音节构成也相对更为复杂，元音前有可能是两个辅音。亚洲语言的**音节**（字）几乎没有两个辅音作为开头的情况，在英文中这种情况却非常普遍。亚洲语言的音节同样没有两三个辅音作为结尾并且还要发声清晰的情况，在英文中这种情况同样非常普遍。每个辅音都要发声清晰的话，就会占用一定的时长。比如，*flexed*, <span class="pho alt">flekst</span>，虽然整体上只是一个音节（<span class="pho">ccvccc</span> 的结构），可即便这个音节中的元音 <span class="pho">e</span> 是短元音，整体发声时它也比任何一个亚洲语言中的 “字”（同样是一个音节）都长。
-
-English syllables can also be more complex, often with two consonants in the beginning of a vowel. This contrasts with Asian languages, where syllables (or *characters*) rarely start with two consonants. Similarly, English often ends syllables with two or three clear-sounding consonants, while this is less common in Asian languages. Each consonant requires a certain amount of time to articulate clearly. For example, the word *flexed*, pronounced <span class="pho alt">flekst</span>, although technically one syllable (<span class="pho">ccvccc</span> structure), takes longer to say than any single syllable (or *character*) in an Asian language, even though the vowel <span class="pho">e</span> in *flexed* is short.
-
-平均来看，英文的音节中**辅音数量**可能是亚洲语言的**两三倍以上** —— 这造成的结果就是，说英文的时候，舌头比说其他语言的时候相对要忙太多…… 并且，因此英文单个音节的发声时长也相对更长 —— 不是长一点点，而是长很多。
-
-On average, the number of consonants in English syllables is likely more than double that of Asian languages. This means that speaking English requires our tongues to be busier than when speaking in most other languages. Moreover, this causes each English syllable to be pronounced in a relatively longer duration - not just a bit longer, but *significantly* longer.
-
-音节上的长短差异会造成语音在韵律和节奏上的巨大差异。
-
-The difference in syllable length can lead to a significant difference in speech prosody and rhythm.
-
-若是忽视了这一点，那么，在节奏韵律上的巨大差异会形成一个无法逾越的障碍。很多人压根就不知道这里有一个巨大的障碍，于是，从来就没有可能跨越它 —— 请问，你如何跨越一个你不知其存在的障碍呢？
-
-If this is overlooked, the resulting significant difference in prosody and rhythm can become an insurmountable barrier. Many people are oblivious to this huge obstacle, hence, they never get the chance to overcome it. After all, how can you overcome a barrier you don't even know exists?
-
-还有另外一个比较隐蔽的却也同样重要的差异：
-
-There's another less noticeable yet equally crucial difference:
-
-> 英语的自然语音中有大量的**塞音**存在于音节之间。这些音我们虽然听不到，也看不到发声器官的动作，但这些动作却是完整完成的 —— 也就是说，它们也是占用时长的。
->
-> In natural English speech, there are numerous *stop* sounds interspersed between syllables. We may not hear these sounds or see the articulator in action, but the actions are fully completed, meaning they also take up time.
-
-还没有完…… 记得吗？两个元音直接连在一起的时候，还有可能存在**加音**（<span class="pho">ʲ/ʷ</span>），以及很常见的 <span class="pho">l</span> 之前的加音 <span class="pho">ᵊ</span>……
-
-And there's more... remember? When two vowels are connected, there might also be a **glide sound** (<span class="pho">ʲ/ʷ</span>), and that common schwa <span class="pho">ᵊ</span> added before <span class="pho">l</span>...
-
-所有这些细节加在一起，造成了一个格外普遍的现象：
-
-All these nuances combined result in a particularly common phenomenon:
-
-> **亚洲人讲英文的时候速度都过快……**
->
-> **Asian people often speak English too quickly...**
-
-常常把**长元音**和**双元音**，以及美式英语特有的**半长元音**读成更短的版本（尤其是 <span class="pho">æ</span>），很多**辅音**没有清楚地发音，很多实际存在的微妙**停顿**（比如**塞音**）全都忽略，甚至可能在某些辅音之后插入了原本**不存在的元音**，但是，反过来常见的**加音**却实际上缺席……
-
-Asian speakers often shorten long vowels and diphthongs, as well as the unique half-long vowels in American English, especially the <span class="pho">æ</span> sound. Many consonants aren't clearly pronounced, and subtle stops that should be there are often overlooked. Sometimes, vowels are added where they don't exist, yet, ironically, added sounds that should be present are often missing.
-
-整体结果就是，同样一句话，亚洲人总是能够做到更快、很快、甚至太快地讲完。可问题在于，从理解的角度来看，在英文母语使用者耳中，几乎所有的韵律和节奏全都是错的。用错误的韵律节奏，讲的速度越快，就越难以被理解。
-
-The result is that Asians tend to speak English much faster than native speakers. The problem, however, is that from a comprehension standpoint, the prosody and rhythm are all wrong to native English ears. The faster you speak with incorrect prosody and rhythm, the harder it becomes to understand.
-
-还没有完……
-
-The story doesn't end there...
-
-另外一个影响初学者讲英文时语速不正常地快的原因，更微妙，来自于一种基于普遍误解的心理压力。在这一点上，全世界的人都一样，当人们听到自己听不懂的另外一种语言的时候，总是**误以为**对方**说话速度很快**。
-
-Another subtle factor that often makes beginners speak English unnaturally fast originates from a psychological pressure based on a widespread misunderstanding. This is a universal experience: when people hear a language they do not understand, they often *mistakenly believe* that the speaker is *talking too fast*.
-
-可这就是因误解而生的幻觉。之所以幻觉对方语速快，是因为自己听不懂。听母语的时候，大脑甚至可以以句子为单位处理信息，可突然之间，要退回到音节级别，又因为那声音里充满了自己并不习惯甚至没听过的音素，不习惯的韵律和节奏，当然需要更多的精力…… 听不懂，当然记不住。于是，大脑更不够用，更是误以为对方说话太快。
-
-However, this perception is nothing but an illusion born out of misunderstanding. The reason we perceive foreign speakers as speaking quickly is simply because we don't understand what they're saying. When we listen to our native language, our brain can process information on the sentence level. Suddenly, when faced with a foreign language, we're thrust back to the syllable level. With unfamiliar phonemes, prosody and rhythms, we, of course, need more mental effort... If we don't understand, we certainly can't remember. As a result, our brains struggle more, enhancing this illusion of rapid speech.
-
-其实，全世界的人在说话的时候，不管使用任何语言都一样，都会不由自主地**划分意群**，下意识地**选择轻重**，并且都会有意无意地**适当停顿**，不仅是在句子之间，句子之内也有。
-
-In reality, all speakers, regardless of the language they're using, instinctively chunk phrases, choose stress levels subconsciously, and take deliberate pauses. These pauses are not only between sentences but also within them.
-
-可是，突然之间，只是因为听不懂、记不住，大脑就像一台同时运行了太多软件的电脑， CPU 过热，内存溢出，恨不得当场死机。于是，不知不觉之间产生了幻觉，就是觉得对方说话快，即便对方正在以再正常不过的语速讲话。
-
-But then, all of a sudden, just because you can't understand or remember, your brain starts working like a computer running too many apps at once. The CPU overheats, memory overflows, and it feels like it's about to crash right there and then. Without realizing it, you start to imagine that the other person is speaking too quickly, even though they're speaking at a perfectly normal pace.
-
-基于上面这个普遍误解的下一个误解，同样微妙，人们常常误以为**语速够快**就能构成**讲得足够流利**。其实，**流利**的构成与**语速快慢**几乎全无关系。是否流利**更多是发音是否正确，措辞是否准确，句法和用法是否符合习惯，逻辑是否顺畅，等等等等 —— 以及，很多人可能并未意识到的另外一个很重要的东西，叫做**节奏**。
-
-Building on the common misconception mentioned above, there's another subtle misperception often held: people tend to equate *speaking fast* with *being fluent*. In reality, *fluency* has almost nothing to do with *the speed of speech*. True fluency hinges on accurate pronunciation, precise choice of words, adherence to customary syntax and usage, smooth logical presentation, and so on. What's more, something many people may not fully realize is the crucial role *rhythm* plays in fluent speech.
-
-所以，刚开始的时候，**要刻意放慢自己的语速**。记住，流利不靠语速，起码不只靠语速。语速过快，容易出错，越快出错越多。再说，流利也不是一上来就需要追求的东西，速度更不是。
-
-So, in the beginning, it's crucial to *deliberately slow down your pace of speech*. Bear in mind, fluency doesn't depend solely on the speed of speech. Speaking too quickly can lead to mistakes, and the faster you speak, the more errors you're likely to make. Besides, fluency isn't something you need to aim for right off the bat, and speed is even less so.
-
-好莱坞动作明星阿诺德·施瓦辛格口音很重但表达清楚且流利 —— 这是怎么回事呢？一般来说，决定一个人讲话**流利与否**的因素，从听众角度出发，如果能够按照重要性排列的话，大抵应该如下：
-
-Consider Hollywood action star Arnold Schwarzenegger. His accent is heavy, but he communicates clearly and fluently - how can this be? Generally, the factors that determine whether a person's speech is *fluent or not* can be lined up in terms of importance from the audience's perspective, roughly as follows:
-
-> - **语意完整**
-> - **Complete in meaning**
-> - **上下文足够丰富**
-> - **Rich in context**
-> - **符合习惯**
-> - **Conforms to common usage**
-> - **逻辑清晰**
-> - **Clear in logic**
-> - **语法正确**
-> - **Correct in grammar**
-> - **措辞准确**
-> - **Accurate in wording**
-> - **发音**
-> - **Pronunciation**
-> >    - 节奏
-> >    - Rhythm
-> >      - 停顿
-> >      - Stop
-> >      - 轻重
-> >      - Emphasis
-> >      - 缓急
-> >      - Pace
-> >    - 韵律
-> >    - Prosody
-> >      - 高低
-> >      - Pitch
-> >      - 起伏
-> >      - Tone
-> >    - 音素
-> >    - Phonemes
-> >      - 元音
-> >      - Vowels
-> >      - 辅音
-> >      - Consonants
-
-即便是到了相对最不重要的**音素**层面，也有重要性上的先后顺序，**元音比辅音更重要**。然而，绝大多数人在整个练习过程中，在最不重要的层面上就被卡住了…… 越是重要的越没机会练习，越是重要的，越没能力去关注 —— 这才是失败的关键吧？
-
-Even at the seemingly least important level of phonemes, there's a hierarchy of importance: *vowels are more critical than consonants*. However, most people get stuck at this least significant level during their practice... The more crucial something is, the less opportunity they have to practice it, the less capacity they have to focus on it. Isn't this the real crux of failure?
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-# 3.2 情绪（Emotions）
-
-学习语音的唯一有效方法只有模仿。在模仿的时候，最难模仿的，其实并不是我们已经讲解过的各种重点…… 还有一个可能无法模仿的，和另外一个其实可以模仿的。
-
-The only effective way to learn speech is by *imitation*. The most challenging part of this process isn't necessarily the key points we've previously discussed... There are two things that may come to mind: one that might be impossible to mimic, and another that could actually be copied.
-
-可能无法模仿的是对方的**音质**，因为到最后，每个人的声音都不一样，声线、音域、音量都不一样…… 通常来说，除非是模仿能力特别强的人，才能做到发出和别人同样音质的声音 —— 虽然不是谁都做不到，但，这个要求多少的确有点过份……
-
-The thing that might be impossible to mimic is someone else's *voice quality*. In the end, each person's voice is unique - the pitch, range, and volume all differ. Usually, only those with a particularly strong ability to imitate can perfectly replicate the voice quality of another. While not impossible, this expectation can indeed be a bit excessive.
-
-然而，的确有确实可以模仿的 —— **情绪**。紧张、兴奋、疲惫、失望、恐惧、悲伤、快乐、期待，等等等等。就算不能模仿得一模一样，终归能按照自己的方式去表现同样的情绪 —— 瞬间就能做到八九不离十。
-
-However, there is something that can certainly be mimicked - *emotions*. Be it nervousness, excitement, fatigue, disappointment, fear, sadness, joy, anticipation, and so on. Even if you can't mimic these emotions identically, you can certainly express the same feelings in your own way - and instantly get pretty close to the mark.
-
-用 AI 生成的真人语音，最大的问题在于，它目前还不能做到**情绪饱满**，它只是尽量做到了 “听起来像是真人说话”，虽然已经很好，但就是缺乏情绪表达 —— 它也的确没有什么真正的情绪……
-
-The biggest issue with AI-generated human voices is that they currently lack emotional depth. They strive to *sound like a human speaking* and while they do this well, they fall short in conveying emotion - which is understandable, as they don't genuinely feel any emotions.
-
-各种惊悚片动作片都很精彩，很吸引人…… 可实际上它们真的不是最好的学习材料，因为这类影视内容的对话事实上非常枯燥，警匪片里最常重复的，只不过是 *Freeze! Drop your gun!* 要么就是 *You have the right to remain silent*... 战争片里最常重复的更加迷离，反反复复最多的都是 *Get down!* 或者 *Go! Go! Go!* —— 动作太多，语言就只能太少。至于情绪么，往往更多的只有愤怒或者悲伤。
-
-Action movies or thrillers may be captivating, but they are not the best study materials. The dialogues in these movies can be quite dry. Police dramas seem to endlessly repeat phrases like *Freeze! Drop your gun!* or *You have the right to remain silent*. In war movies, you'll frequently hear *Get down!* or *Go! Go! Go!* The abundance of action scenes leaves little room for language. As for emotions, only expressions of anger and sadness tend to dominate.
-
-这就是为什么**生活情景剧**和**脱口秀**常常是很好的学习材料的重要原因 —— 主要是情绪丰富且饱满。另外，**纪录片**往往都是很好的学习材料。它们的特点是，措辞简单明了，语速慢，吐字清晰，并且情绪饱满。情绪更加饱满的，是各种给青少年甚至婴幼儿看的动画片或者绘本讲解，情绪丰富饱满到夸张的地步……
-
-That's why *sitcoms* and *talk shows* often make great learning resources. They are rich in emotional content. *Documentaries* can also serve as excellent study materials, which feature simple and clear wording, slow speech, clear articulation, and full emotions. Even more emotionally expressive are *shows and storybooks for teenagers and toddlers*, where emotions are exaggerated to the extreme.
-
-如果觉得这些都太尴尬，还有个办法是不断学唱**英文歌曲** —— 每个音节都带着不同的音高曲调，甚至有可能一个词就唱了满满一两个小节，容不得一丝的错误，真的是绝佳的练习场景。
-
-If you find these a bit awkward, another approach is to continuously learn English *songs*. Each syllable carries a different tone or melody, and a single word could fill a couple of bars, leaving no room for errors. It's indeed an excellent practice setting.
-
-语音的功用，如果说有 *20%* 是用来传递对事实的感受的话，那么，剩下的 *80%* 肯定并且只能用来传递情绪，不是吗？一直以来，大家在 “学外语” 的时候，都太理智了，不是吗？理智的确是一种很好的品质，但，有时候，它可能会成为不可逾越的障碍…… 真的很可惜！
-
-If we say that *20%* of voice utility is for conveying feelings towards *facts*, then the remaining *80%* must be intended to express *emotions*, right? Perhaps we've been too logical when learning foreign languages, haven't we? While rationality is a good trait, it can sometimes turn into an insurmountable hurdle... which is truly a pity!
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-# 4. 而后（What's next）
-
-语音是可以通过 3 ～ 6 个月的密集训练彻底搞定的 —— 至少可以获得极大的改善。下一步是什么？下一步是搞定语言的另一方面，除了语音之外的文字 —— 任何语言都一样，都是且只是语音和文字的组合。
-
-With 3 to 6 months of intensive practice, you can really nail pronunciation — at least, you can see huge improvements. So, what's next? The next step is to master the other side of the language: the written word. Every language boils down to a combination of speaking and writing.
-
-文字的最基本要素是词汇。英文的词汇基本上是 “拼音文字”。英文的拼写，若是借用中文概念的话，有两种，一种 “表音”，一种 “表意” —— 或者 “既表音又表意”。
-
-```mermaid
-flowchart LR
-spellings(拼写)-...-phonetic-parts(音节)-...-sound&meaning(发音)
-spellings<-----> sound&meaning
-spellings(拼写)-...-semantic-parts(构件)-...-sound&meaning(含义及发音)
-```
-
-The most basic element of writing is vocabulary. English words are fundamentally "phonetic script." If we borrow concepts from Chinese, English spelling falls into two categories: one is "phonetic," the other is "semantic" — or sometimes "both phonetic and semantic."
-
-```mermaid
-flowchart LR
-spellings(spellings)-..-phonetic-parts(phonetic parts)-..-meanings&sounds(meanings & sounds)
-spellings(spellings)<---->meanings&sounds(meanings & sounds)
-spellings(spellings)-..-*semantic*-parts(semantic parts)-..-meanings&sounds(meanings & sounds)
-```
-
-比如，*apple* <span class="pho alt">ˈæp.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/apple-us-male.mp3" data-audio-us-female="/audios/us/apple-us-female.mp3"></span> 就是一个表音构成的词汇，总计两个音节，*app* 对应着第一个音节 <span class="pho alt">ˈæp</span>，*le* 对应着第二个音节 <span class="pho alt">əl</span>。所以，记忆它的时候，不是一个字母一个字母地背，说，“a、p、p、l、e…… *apple!*”。而是：<span class="pho alt">æ</span> 对应着 *a*；*app*，<span class="pho alt">p</span> 的拼写是两个叠加的 *pp*，而后是 <span class="pho alt">le</span> 对应着 <span class="pho alt">əl</span> —— 这样的拼写很常见，比如，*double* <span class="pho alt">ˈdʌb.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/double-us-male.mp3" data-audio-us-female="/audios/us/double-us-female.mp3"></span>, *impossible* <span class="pho alt">ɪmˈpɑː.sə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/impossible-us-male.mp3" data-audio-us-female="/audios/us/impossible-us-female.mp3"></span>……
-
-For example, *apple* <span class="pho alt">ˈæp.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/apple-us-male.mp3" data-audio-us-female="/audios/us/apple-us-female.mp3"></span> is *phonetic* and has two syllables. The first syllable is *app* <span class="pho alt">ˈæp</span>, and the second syllable is *le* <span class="pho alt">əl</span>. So, when you’re memorizing it, you don’t go letter by letter saying, "a, p, p, l, e... *apple!*". Instead, think of it like this: <span class="pho alt">æ</span> matches with *a*; *app* includes <span class="pho alt">p</span> spelled as double *pp*, and then <span class="pho alt">le</span> matches with <span class="pho alt">əl</span>. This spelling pattern is quite common, for example, in words like *double* <span class="pho alt">ˈdʌb.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/double-us-male.mp3" data-audio-us-female="/audios/us/double-us-female.mp3"></span> and *impossible* <span class="pho alt">ɪmˈpɑː.sə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/impossible-us-male.mp3" data-audio-us-female="/audios/us/impossible-us-female.mp3"></span>.
-
-另外，常用词汇中其实有不少是 “组合词汇”（*compound words*），各个组成部分也都是 “表意” 的。比如 *classroom* <span class="pho alt">ˈklæs.ruːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/classroom-us-male.mp3" data-audio-us-female="/audios/us/classroom-us-female.mp3"></span>, *doorbell* <span class="pho alt">ˈdɔːr.bel</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/doorbell-us-male.mp3" data-audio-us-female="/audios/us/doorbell-us-female.mp3"></span>, *handwriting* <span class="pho alt">ˈhændˌraɪ.t̬ɪŋ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/handwriting-us-male.mp3" data-audio-us-female="/audios/us/handwriting-us-female.mp3"></span>, *sunshine* <span class="pho alt">ˈsʌn.ʃaɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sunshine-us-male.mp3" data-audio-us-female="/audios/us/sunshine-us-female.mp3"></span>, *upstairs* <span class="pho alt">ʌpˈsterz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/upstairs-us-male.mp3" data-audio-us-female="/audios/us/upstairs-us-female.mp3"></span> 等等。
-
-Besides, there are quite a few common words that are actually compound words, with each part contributing to the overall meaning, that is, they are *semantic*. For example, *classroom* <span class="pho alt">ˈklæs.ruːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/classroom-us-male.mp3" data-audio-us-female="/audios/us/classroom-us-female.mp3"></span>, *doorbell* <span class="pho alt">ˈdɔːr.bel</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/doorbell-us-male.mp3" data-audio-us-female="/audios/us/doorbell-us-female.mp3"></span>, *handwriting* <span class="pho alt">ˈhændˌraɪ.t̬ɪŋ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/handwriting-us-male.mp3" data-audio-us-female="/audios/us/handwriting-us-female.mp3"></span>, *sunshine* <span class="pho alt">ˈsʌn.ʃaɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sunshine-us-male.mp3" data-audio-us-female="/audios/us/sunshine-us-female.mp3"></span>, *upstairs* <span class="pho alt">ʌpˈsterz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/upstairs-us-male.mp3" data-audio-us-female="/audios/us/upstairs-us-female.mp3"></span>, and so on.
-
-词根词缀，尤其是那些来自于拉丁语的词根词缀，在词汇量没达到一定程度之前，实际用处并不大 —— 但，到了一定地步，比如，词汇量超过 5,000 的时候，在这样扎实的基础上，稍微研究一下词根词缀，对快速且大量地做大词汇量是很有帮助的。
-
-Roots and affixes, especially those from Latin, aren’t very useful until your vocabulary reaches a certain level. But once you get to around 5,000 words, having a solid foundation, delving into roots and affixes can really help you expand your vocabulary quickly and significantly.
-
-举个例子，*ichthyosaur* <span class="pho alt">ˈɪk.θi.ə.sɔːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/ichthyosaur-us-male.mp3" data-audio-us-female="/audios/us/ichthyosaur-us-female.mp3"></span>，这个一看就知道并非常用的词汇，其实很简单，先从表音构成去看，<span class="pho alt">ˈɪk.θi.ə.sɔːr</span> —— 剑桥词典把它划分成了 4 个音节…… 但感觉上，第二第三个音节可以合并，<span class="pho alt">ˈɪk.θiə.sɔːr</span>，*ich* ⭤ <span class="pho alt">ˈɪk</span>, *thyo* ⭤ <span class="pho alt">θiə</span>, *saur* ⭤ <span class="pho alt">sɔːr</span>…… 而从表意的角度去看呢？前半部 *ichthyo-* 的意思是 “与鱼有关的”…… 后半部 *-saur* 是什么意思呢？各种恐龙的 “龙” 都是 -saur 结尾，于是，这个词的意思是 “鱼龙”…… 换言之，这个单词的两个部分，都是拉丁词根词缀，也都是 “既表音又表意” 的，事实上很简单 —— 虽然拼写乍看起来很复杂。
-
-Take *ichthyosaur* for example: <span class="pho alt">ˈɪk.θi.ə.sɔːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/ichthyosaur-us-male.mp3" data-audio-us-female="/audios/us/ichthyosaur-us-female.mp3"></span>. At a glance, you can tell it's not a common word. But it's actually quite simple. Let’s break it down by its sounds. The Cambridge Dictionary splits it into four syllables: <span class="pho alt">ˈɪk.θi.ə.sɔːr</span>. However, the second and third syllables feel like they can be combined: <span class="pho alt">ˈɪk.θiə.sɔːr</span>. So, *ich* is <span class="pho alt">ˈɪk</span>, *thyo* is <span class="pho alt">θiə</span>, and *saur* is <span class="pho alt">sɔːr</span>. From a *semantic* perspective, the first part, *ichthyo-*, means "related to fish." The second part, *-saur*, means "lizard" or "reptile," like in many dinosaur names that end in *-saur*. So, the word *ichthyosaur* means "*fish lizard*" or "*fish reptile*." In other words, this word's parts, drawn from Latin roots and suffixes, make it both *phonetically* and *semantically* simple, even if its spelling looks complicated at first glance.
-
-记忆词汇的最朴素最有效方法，就是把它的拼写、读音和意义联系起来 —— 这原本是文字本来的结构和意义。
-
-```mermaid
-flowchart LR
-
-sounds(读音)<--->meanings(意义)
-meanings<--->spellings(拼写)
-sounds<--->spellings
-```
-
-The simplest and most effective way to remember vocabulary is to connect its spelling, pronunciation, and meaning. This is essentially the structure and purpose of words.
-
-```mermaid
-flowchart LR
-
-sounds(sounds)<--->meanings(meanings)
-meanings<--->spellings(spellings)
-sounds<--->spellings
-```
-
-所以，背单词的时候，要边说边写，即然说出来了就能听得到，即然写出来了就能看得到 —— 它应该是一个同时调动多个感官的活动。
-
-When you're building vocabulary, you should say and write the words at the same time. If you speak it, you hear it. If you write it, you see it. It should be an activity that engages multiple senses at once.
-
-除此之外，其他的任何所谓的 “方法”，都不仅无效，甚至只有副作用，弊大于利。比如什么 “谐音记忆法” 或者 “趣味记忆法” 什么的，它们都违背大脑对语言文字的基本工作机制，根本不可能提高效率，只会增加不必要的负担 —— 虽然有时候觉竟然觉得有点意思……
-
-Apart from this approach, any other so-called "method" is not only ineffective but also counterproductive. Techniques like "homonym mnemonics" or "fun memory tricks" go against how the brain naturally processes language, speaking or writing. They don't improve efficiency; they just add unnecessary work, even if they sometimes seem somewhat amusing.
-
-人们失败的原因很简单，他们总想 “更省事儿一点”。坐在那里只用眼睛看，既不动口也不动手，也因此实际上更少动脑。只调用一个器官和同时调用多个器官是不一样的，前者好像更省事儿，可实际上由于脑力调用太少，导致的结果是 “效果几近于零”。
-
-The reason people fail is simple: they want to take the easy way out. They just sit there looking at words with their eyes, without speaking or writing, which means they engage their brains less. Using just one sense is not the same as using multiple senses simultaneously. The former might seem easier, but due to minimal brain engagement, the results are almost negligible.
-
-学外语的人十有八九失败。很多失败的人都曾经去问过老师，“老师，我背单词不记发音行不行？” “老师，我背单词不记拼写行不行？” 这种荒谬至极的问题问出来，并不是想要什么答案，只是想要一个 “偷懒认证”，给自己的偷懒找个背书…… 还别说，还真有老师说 “可以！” 因为真的有相当数量相当比例的老师，通过这种方法获得更多来自学生的好感，进而提高自己的收入……
-
-Most people fail at learning a new language. Many of them have asked their teachers, "Can I memorize words without learning their pronunciation?" or "Can I memorize words without learning how to spell them?" These absurd questions aren't looking for real answers; they are just seeking a justification to cut corners. And believe it or not, some teachers say "yes" to gain popularity and, as a result, increase their income.
-
-扩充词汇，是有 “加速度” 的过程 —— 可以越来越快…… 可是，在最初的时候，速度很低，加速度为零，所以总是感觉超级吃力。然而，词汇之间是有关联的，对大脑来说，一个生词与已有的词汇关联越多，越容易记住。也就是说，已有词汇量越多，新词可能与它们产生的关联越多，所以才越来越容易。当你的词汇量超过三五千的时候，你就会感觉很多生词几乎看一眼就记得住，无论是拼写还是读音还是其意义甚至其用法。
-
-Building your vocabulary has a snowball effect—you can pick up speed as you go. However, at the beginning, the speed is very low, and it feels incredibly hard. Words are interconnected. For your brain, the more links a new word has with the words you already know, the easier it is to remember. So, the larger your vocabulary, the more connections there are, and it becomes increasingly easier to learn new words. When your vocabulary exceeds three to five thousand words, you'll find that you can almost remember new words at a glance, including their spelling, pronunciation, meaning, and even usage.
-
-所以有个窍门。**直接背例句**…… 对大脑来说，“多朗读几遍例句” 远比 “只把力气花在某一个单词或者词组上” 来得更为轻松。在语言方面就是这样，你做得越多，对大脑来说越轻松，反过来，你做得越少，所谓 “省事儿” 逐步形成的，对大脑来说只能是不可逾越的障碍。
-
-Here's a tip: *memorize **sentences** directly*. For your brain, reading a few example sentences repeatedly is much easier than focusing all your effort on a single word or phrase. In language learning, the more you do, the easier it gets for your brain. Conversely, the less you do, the so-called "easier way" forms an insurmountable obstacle.
-
-进而，最靠谱的扩大词汇量方法：**精读**。找到自己真正感兴趣的书（小说类、非小说类各几本），遇到生词就查，逐一消灭 —— 每本书都要读若干遍（所以一定要选自己真迷恋的书）…… 读着读着，词汇量就大了，句法障碍就消失了，理解能力就提高了，阅读速度就飞快了…… 各种语言都是这样的。哪怕是我们的母语，我们对母语的掌控能力，也是这么练出来的 —— 学校里的语文课和语文老师，从来都帮不上什么忙…… 说点刻薄的话，这些语文老师啊，他们的唯一作用就是在考试里给绝大多数学生设置奇怪的障碍。
-
-The most reliable method to expand your vocabulary is *intensive reading*. Find books you are genuinely interested in (both fiction and non-fiction). Look up unfamiliar words and eliminate them one by one. Read each book several times, so make sure you really love these books. As you read, your vocabulary will grow, syntax barriers will disappear, your comprehension will improve, and your reading speed will soar. This applies to all languages. Even in our native language, our proficiency comes from practice—not from schools or language teachers. In fact, these teachers often only serve to create odd obstacles in exams.
diff --git a/1000-hours/sounds-of-american-english-old/4.1-multisounds.md b/1000-hours/sounds-of-american-english-old/4.1-multisounds.md
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-# 4.1. 多音拼写（Spellings with multiple sounds）
-
-之前的章节里，都罗列了对应每个音素可能的拼写。有些拼写只对应一个读音，比如，**h** 就只对应着 <span class="pho">h</span>；但，有一些拼写可能对应着多个读音。以下是一个总结整理，需要经过反复对照而谙熟于心。
-
-In the previous chapters, we listed the possible spellings for each phoneme. Some spellings correspond to just one sound, like **h**, which only corresponds to <span class="pho">h</span>. However, some spellings can correspond to multiple sounds. Here's a summary that needs to be reviewed repeatedly until it becomes second nature.
-
-## 4.1.1. 元音拼写（Spellings of Vowels）
-
-- "**a**": `ɑː`, `æ`, `e`, `eɪ`, `ə`
-- "**ai**": `e`, `eɪ`
-- "**al**": `ɑː`, `æ`, `ɔː`
-- "**ar**": `ɑːr`, `ɚ`
-- "**au**": `ɑː`, `aʊ`, `ɔː`
-- "**e**": `e`, `ə`, `ɪ`, `iː`
-- "**ea**": `e`, `iː`, `eɪ`
-- "**ear**": `er`, `ɪr`, `ɝː`
-- "**er**": `ɚ`, `ɝː`
-- "**ew**": `uː`, `oʊ`
-- "**i**": `ɪ`, `aɪ`, `ə`, `j`,
-- "**ie**": `iː`, `e`, `aɪ`
-- "**o**": `ʌ`, `ɑː`, `ə`, `ɔː`, `uː`, `oʊ`
-- "**oo**": `ʌ`, `ʊ`, `uː`
-- "**oor**": `ʊr`, `ɔːr`
-- "**or**": `ɚ`, `ɝː`, `ɔːr`
-- "**ou**": `ʌ`, `ʊ`, `ə`, `aʊ`
-- "**ough**": `ɑː`, `oʊ`
-- "**our**": `aʊr`, `ʊr`, `ɔːr`
-- "**ow**": `aʊ`, `oʊ`
-- "**u**": `ʌ`, `ʊ`, `uː`, `ə`
-- "**ure**": `ɚ`, `ʊr`
-
-## 4.1.2. 辅音拼写（Spellings of Consonants）
-
-- "**c**": `s`, `k`
-- "**ch**": `ʃ`, `k`, `ʧ`
-- "**d**": `d`, `dʒ`
-- "**g**": `g`, `dʒ`, `ʒ`
-- "**j**": `j`, `dʒ`
-- "**s**": `s`, `z`, `ʃ`, `ʒ`
-- "**ss**": `s`, `ʃ`
-- "**th**": `ð`, `θ`, `t`
-- "**y**": `ɪ`, `aɪ`, `i`, `j`
-- "**z**": `z`, `ʒ`
\ No newline at end of file
diff --git a/1000-hours/sounds-of-american-english-old/4.2-compounds.md b/1000-hours/sounds-of-american-english-old/4.2-compounds.md
deleted file mode 100644
index 2b783497..00000000
--- a/1000-hours/sounds-of-american-english-old/4.2-compounds.md
+++ /dev/null
@@ -1,60 +0,0 @@
-## 4.2. 常见组合词汇（Compound words）
-
-1. airplane <span class="pho alt">ˈer.pleɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/airplane-us-male.mp3" data-audio-us-female="/audios/us/airplane-us-female.mp3"></span>
-2. airport <span class="pho alt">ˈer.pɔːrt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/airport-us-male.mp3" data-audio-us-female="/audios/us/airport-us-female.mp3"></span>
-3. backyard <span class="pho alt">ˌbækˈjɑːrd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/backyard-us-male.mp3" data-audio-us-female="/audios/us/backyard-us-female.mp3"></span>
-4. bedroom <span class="pho alt">ˈbed.ruːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bedroom-us-male.mp3" data-audio-us-female="/audios/us/bedroom-us-female.mp3"></span>
-5. birthday <span class="pho alt">ˈbɝːθ.deɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/birthday-us-male.mp3" data-audio-us-female="/audios/us/birthday-us-female.mp3"></span>
-6. blackboard <span class="pho alt">ˈblæk.bɔːrd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/blackboard-us-male.mp3" data-audio-us-female="/audios/us/blackboard-us-female.mp3"></span>
-7. bookstore <span class="pho alt">ˈbʊk.stɔːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/bookstore-us-male.mp3" data-audio-us-female="/audios/us/bookstore-us-female.mp3"></span>
-8. brainstorm <span class="pho alt">ˈbreɪn.stɔːrm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/brainstorm-us-male.mp3" data-audio-us-female="/audios/us/brainstorm-us-female.mp3"></span>
-9. breakfast <span class="pho alt">ˈbrek.fəst</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/breakfast-us-male.mp3" data-audio-us-female="/audios/us/breakfast-us-female.mp3"></span>
-10. classroom <span class="pho alt">ˈklæs.ruːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/classroom-us-male.mp3" data-audio-us-female="/audios/us/classroom-us-female.mp3"></span>
-11. cupcake <span class="pho alt">ˈkʌp.keɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/cupcake-us-male.mp3" data-audio-us-female="/audios/us/cupcake-us-female.mp3"></span>
-12. daydream <span class="pho alt">ˈdeɪ.driːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/daydream-us-male.mp3" data-audio-us-female="/audios/us/daydream-us-female.mp3"></span>
-13. dishwasher <span class="pho alt">ˈdɪʃˌwɑː.ʃɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/dishwasher-us-male.mp3" data-audio-us-female="/audios/us/dishwasher-us-female.mp3"></span>
-14. doorbell <span class="pho alt">ˈdɔːr.bel</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/doorbell-us-male.mp3" data-audio-us-female="/audios/us/doorbell-us-female.mp3"></span>
-15. downtown <span class="pho alt">ˌdaʊnˈtaʊn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/downtown-us-male.mp3" data-audio-us-female="/audios/us/downtown-us-female.mp3"></span>
-16. earthquake <span class="pho alt">ˈɝːθ.kweɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/earthquake-us-male.mp3" data-audio-us-female="/audios/us/earthquake-us-female.mp3"></span>
-17. everyday <span class="pho alt">ˈev.ri.deɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/everyday-us-male.mp3" data-audio-us-female="/audios/us/everyday-us-female.mp3"></span>
-18. eyewitness <span class="pho alt">ˈaɪˌwɪt.nəs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/eyewitness-us-male.mp3" data-audio-us-female="/audios/us/eyewitness-us-female.mp3"></span>
-19. firefighter <span class="pho alt">ˈfaɪrˌfaɪ.t̬ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/firefighter-us-male.mp3" data-audio-us-female="/audios/us/firefighter-us-female.mp3"></span>
-20. football <span class="pho alt">ˈfʊt.bɑːl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/football-us-male.mp3" data-audio-us-female="/audios/us/football-us-female.mp3"></span>
-21. greenhouse <span class="pho alt">ˈɡriːn.haʊs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/greenhouse-us-male.mp3" data-audio-us-female="/audios/us/greenhouse-us-female.mp3"></span>
-22. handwriting <span class="pho alt">ˈhændˌraɪ.t̬ɪŋ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/handwriting-us-male.mp3" data-audio-us-female="/audios/us/handwriting-us-female.mp3"></span>
-23. headache <span class="pho alt">ˈhed.eɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/headache-us-male.mp3" data-audio-us-female="/audios/us/headache-us-female.mp3"></span>
-24. highway <span class="pho alt">ˈhaɪ.weɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/highway-us-male.mp3" data-audio-us-female="/audios/us/highway-us-female.mp3"></span>
-25. homework <span class="pho alt">ˈhoʊm.wɝːk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/homework-us-male.mp3" data-audio-us-female="/audios/us/homework-us-female.mp3"></span>
-26. iceberg <span class="pho alt">ˈaɪs.bɝːɡ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/iceberg-us-male.mp3" data-audio-us-female="/audios/us/iceberg-us-female.mp3"></span>
-27. jellyfish <span class="pho alt">ˈdʒel.i.fɪʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/jellyfish-us-male.mp3" data-audio-us-female="/audios/us/jellyfish-us-female.mp3"></span>
-28. laptop <span class="pho alt">ˈlæp.tɑːp</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/laptop-us-male.mp3" data-audio-us-female="/audios/us/laptop-us-female.mp3"></span>
-29. lighthouse <span class="pho alt">ˈlaɪt.haʊs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/lighthouse-us-male.mp3" data-audio-us-female="/audios/us/lighthouse-us-female.mp3"></span>
-30. mailbox <span class="pho alt">ˈmeɪl.bɑːks</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/mailbox-us-male.mp3" data-audio-us-female="/audios/us/mailbox-us-female.mp3"></span>
-31. moonlight <span class="pho alt">ˈmuːn.laɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/moonlight-us-male.mp3" data-audio-us-female="/audios/us/moonlight-us-female.mp3"></span>
-32. notebook <span class="pho alt">ˈnoʊt.bʊk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/notebook-us-male.mp3" data-audio-us-female="/audios/us/notebook-us-female.mp3"></span>
-33. nobody <span class="pho alt">ˈnoʊ.bɑː.di</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/nobody-us-male.mp3" data-audio-us-female="/audios/us/nobody-us-female.mp3"></span>
-34. pancake <span class="pho alt">ˈpæn.keɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pancake-us-male.mp3" data-audio-us-female="/audios/us/pancake-us-female.mp3"></span>
-35. postcard <span class="pho alt">ˈpoʊst.kɑːrd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/postcard-us-male.mp3" data-audio-us-female="/audios/us/postcard-us-female.mp3"></span>
-36. rainbow <span class="pho alt">ˈreɪn.boʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/rainbow-us-male.mp3" data-audio-us-female="/audios/us/rainbow-us-female.mp3"></span>
-37. sailboat <span class="pho alt">ˈseɪl.boʊt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sailboat-us-male.mp3" data-audio-us-female="/audios/us/sailboat-us-female.mp3"></span>
-38. sandbox <span class="pho alt">ˈsænd.bɑːks</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sandbox-us-male.mp3" data-audio-us-female="/audios/us/sandbox-us-female.mp3"></span>
-39. seashore <span class="pho alt">ˈsiː.ʃɔːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/seashore-us-male.mp3" data-audio-us-female="/audios/us/seashore-us-female.mp3"></span>
-40. skateboard <span class="pho alt">ˈskeɪt.bɔːrd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/skateboard-us-male.mp3" data-audio-us-female="/audios/us/skateboard-us-female.mp3"></span>
-41. snowflake <span class="pho alt">ˈsnoʊ.fleɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/snowflake-us-male.mp3" data-audio-us-female="/audios/us/snowflake-us-female.mp3"></span>
-42. spaceship <span class="pho alt">ˈspeɪs.ʃɪp</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/spaceship-us-male.mp3" data-audio-us-female="/audios/us/spaceship-us-female.mp3"></span>
-43. sunflower <span class="pho alt">ˈsʌnˌflaʊ.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sunflower-us-male.mp3" data-audio-us-female="/audios/us/sunflower-us-female.mp3"></span>
-44. sunshine <span class="pho alt">ˈsʌn.ʃaɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sunshine-us-male.mp3" data-audio-us-female="/audios/us/sunshine-us-female.mp3"></span>
-45. superhero <span class="pho alt">ˈsuː.pɚˌhɪr.oʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/superhero-us-male.mp3" data-audio-us-female="/audios/us/superhero-us-female.mp3"></span>
-46. tablecloth <span class="pho alt">ˈteɪ.bəl.klɑːθ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/tablecloth-us-male.mp3" data-audio-us-female="/audios/us/tablecloth-us-female.mp3"></span>
-47. toothbrush <span class="pho alt">ˈtuːθ.brʌʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/toothbrush-us-male.mp3" data-audio-us-female="/audios/us/toothbrush-us-female.mp3"></span>
-48. toothpaste <span class="pho alt">ˈtuːθ.peɪst</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/toothpaste-us-male.mp3" data-audio-us-female="/audios/us/toothpaste-us-female.mp3"></span>
-49. typewriter <span class="pho alt">ˈtaɪpˌraɪ.t̬ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/typewriter-us-male.mp3" data-audio-us-female="/audios/us/typewriter-us-female.mp3"></span>
-50. underwater <span class="pho alt">ˌʌn.dɚˈwɑː.t̬ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/underwater-us-male.mp3" data-audio-us-female="/audios/us/underwater-us-female.mp3"></span>
-51. upstairs <span class="pho alt">ʌpˈsterz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/upstairs-us-male.mp3" data-audio-us-female="/audios/us/upstairs-us-female.mp3"></span>
-52. volleyball <span class="pho alt">ˈvɑː.li.bɑːl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/volleyball-us-male.mp3" data-audio-us-female="/audios/us/volleyball-us-female.mp3"></span>
-53. waterfall <span class="pho alt">ˈwɑː.t̬ɚ.fɑːl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/waterfall-us-male.mp3" data-audio-us-female="/audios/us/waterfall-us-female.mp3"></span>
-54. watermelon <span class="pho alt">ˈwɑː.t̬ɚˌmel.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/watermelon-us-male.mp3" data-audio-us-female="/audios/us/watermelon-us-female.mp3"></span>
-55. weekend <span class="pho alt">ˈwiːk.end</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/weekend-us-male.mp3" data-audio-us-female="/audios/us/weekend-us-female.mp3"></span>
-56. wheelchair <span class="pho alt">ˈwiːl.tʃer</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/wheelchair-us-male.mp3" data-audio-us-female="/audios/us/wheelchair-us-female.mp3"></span>
-57. windmill <span class="pho alt">ˈwɪnd.mɪl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/windmill-us-male.mp3" data-audio-us-female="/audios/us/windmill-us-female.mp3"></span>
-58. workshop <span class="pho alt">ˈwɝːk.ʃɑːp</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/workshop-us-male.mp3" data-audio-us-female="/audios/us/workshop-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/4.3-components.md b/1000-hours/sounds-of-american-english-old/4.3-components.md
deleted file mode 100644
index 5d6e665a..00000000
--- a/1000-hours/sounds-of-american-english-old/4.3-components.md
+++ /dev/null
@@ -1,5 +0,0 @@
-## 4.3 常见词根词缀（Common Roots and Affixes）
-
-英文的词根大多来自拉丁语；而常用词缀，包括前缀和后缀 —— 它们都是表意的。
-
-Most English word *roots* come from Latin, while commonly used *affixes*, including *prefixes* and *suffixes*, carry specific meanings, that is, *semantic*.
\ No newline at end of file
diff --git a/1000-hours/sounds-of-american-english-old/4.3.1-prefixes.md b/1000-hours/sounds-of-american-english-old/4.3.1-prefixes.md
deleted file mode 100644
index 5b4acba3..00000000
--- a/1000-hours/sounds-of-american-english-old/4.3.1-prefixes.md
+++ /dev/null
@@ -1,101 +0,0 @@
-### 4.3.1. 常见前缀（Common Prefixes）
-
-1. **un-** (not, opposite of)
-  * unhappy <span class="pho alt">ʌnˈhæp.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/unhappy-us-male.mp3" data-audio-us-female="/audios/us/unhappy-us-female.mp3"></span>
-  * unknown <span class="pho alt">ʌnˈnoʊn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/unknown-us-male.mp3" data-audio-us-female="/audios/us/unknown-us-female.mp3"></span>
-  * unusual <span class="pho alt">ʌnˈjuː.ʒu.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/unusual-us-male.mp3" data-audio-us-female="/audios/us/unusual-us-female.mp3"></span>
-
-2. **re-** (again, back)
-  * redo <span class="pho alt">riːˈduː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/redo-us-male.mp3" data-audio-us-female="/audios/us/redo-us-female.mp3"></span>
-  * review <span class="pho alt">rɪˈvjuː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/review-us-male.mp3" data-audio-us-female="/audios/us/review-us-female.mp3"></span>
-  * return <span class="pho alt">rɪˈtɝːn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/return-us-male.mp3" data-audio-us-female="/audios/us/return-us-female.mp3"></span>
-
-3. **in-** (not, into)
-  * incomplete <span class="pho alt">ˌɪn.kəmˈpliːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/incomplete-us-male.mp3" data-audio-us-female="/audios/us/incomplete-us-female.mp3"></span>
-  * invisible <span class="pho alt">ɪnˈvɪz.ə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/invisible-us-male.mp3" data-audio-us-female="/audios/us/invisible-us-female.mp3"></span>
-  * inside <span class="pho alt">ɪnˈsaɪd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/inside-us-male.mp3" data-audio-us-female="/audios/us/inside-us-female.mp3"></span>
-
-4. **dis-** (not, opposite of)
-  * disagree <span class="pho alt">ˌdɪs.əˈɡriː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/disagree-us-male.mp3" data-audio-us-female="/audios/us/disagree-us-female.mp3"></span>
-  * disappear <span class="pho alt">ˌdɪs.əˈpɪr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/disappear-us-male.mp3" data-audio-us-female="/audios/us/disappear-us-female.mp3"></span>
-  * disconnect <span class="pho alt">ˌdɪs.kəˈnekt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/disconnect-us-male.mp3" data-audio-us-female="/audios/us/disconnect-us-female.mp3"></span>
-
-5. **pre-** (before)
-  * preview <span class="pho alt">ˈpriː.vjuː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/preview-us-male.mp3" data-audio-us-female="/audios/us/preview-us-female.mp3"></span>
-  * predict <span class="pho alt">prɪˈdɪkt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/predict-us-male.mp3" data-audio-us-female="/audios/us/predict-us-female.mp3"></span>
-  * preschool <span class="pho alt">ˈpriː.skuːl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/preschool-us-male.mp3" data-audio-us-female="/audios/us/preschool-us-female.mp3"></span>
-
-6. **mis-** (wrongly)
-  * misunderstand <span class="pho alt">ˌmɪs.ʌn.dɚˈstænd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/misunderstand-us-male.mp3" data-audio-us-female="/audios/us/misunderstand-us-female.mp3"></span>
-  * misplace <span class="pho alt">ˌmɪsˈpleɪs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/misplace-us-male.mp3" data-audio-us-female="/audios/us/misplace-us-female.mp3"></span>
-  * mislead <span class="pho alt">ˌmɪsˈliːd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/mislead-us-male.mp3" data-audio-us-female="/audios/us/mislead-us-female.mp3"></span>
-
-7. **non-** (not)
-  * nonstick <span class="pho alt">ˌnɑːnˈstɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/nonstick-us-male.mp3" data-audio-us-female="/audios/us/nonstick-us-female.mp3"></span>
-  * nonprofit <span class="pho alt">nɑnˈprɑf·ɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/nonprofit-us-male.mp3" data-audio-us-female="/audios/us/nonprofit-us-female.mp3"></span>
-  * nonviolent <span class="pho alt">ˌnɑːnˈvaɪə.lənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/nonviolent-us-male.mp3" data-audio-us-female="/audios/us/nonviolent-us-female.mp3"></span>
-
-8. **over-** (too much)
-  * overeat <span class="pho alt">ˌoʊ.vɚˈiːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/overeat-us-male.mp3" data-audio-us-female="/audios/us/overeat-us-female.mp3"></span>
-  * overwork <span class="pho alt">ˌoʊ.vɚˈwɝːk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/overwork-us-male.mp3" data-audio-us-female="/audios/us/overwork-us-female.mp3"></span>
-  * overheat <span class="pho alt">ˌoʊ.vɚˈhiːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/overheat-us-male.mp3" data-audio-us-female="/audios/us/overheat-us-female.mp3"></span>
-
-9. **sub-** (under)
-  * submarine <span class="pho alt">ˌsʌb.məˈriːn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/submarine-us-male.mp3" data-audio-us-female="/audios/us/submarine-us-female.mp3"></span>
-  * subtitle <span class="pho alt">ˈsʌbˌtaɪ.t̬əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/subtitle-us-male.mp3" data-audio-us-female="/audios/us/subtitle-us-female.mp3"></span>
-  * subconscious <span class="pho alt">ˌsʌbˈkɑːn.ʃəs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/subconscious-us-male.mp3" data-audio-us-female="/audios/us/subconscious-us-female.mp3"></span>
-
-10. **inter-** (between, among)
-  * international <span class="pho alt">ˌɪn.t̬ɚˈnæʃ.ən.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/international-us-male.mp3" data-audio-us-female="/audios/us/international-us-female.mp3"></span>
-  * interact <span class="pho alt">ˌɪn.t̬ɚˈækt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/interact-us-male.mp3" data-audio-us-female="/audios/us/interact-us-female.mp3"></span>
-  * interrupt <span class="pho alt">ˌɪn.t̬əˈrʌpt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/interrupt-us-male.mp3" data-audio-us-female="/audios/us/interrupt-us-female.mp3"></span>
-
-11. **trans-** (across, beyond)
-  * transport <span class="pho alt">ˈtræn.spɔːrt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/transport-us-male.mp3" data-audio-us-female="/audios/us/transport-us-female.mp3"></span>
-  * transfer <span class="pho alt">ˈtræns.fɝː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/transfer-us-male.mp3" data-audio-us-female="/audios/us/transfer-us-female.mp3"></span>
-  * transform <span class="pho alt">trænsˈfɔːrm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/transform-us-male.mp3" data-audio-us-female="/audios/us/transform-us-female.mp3"></span>
-
-12. **under-** (too little, below)
-  * underpaid <span class="pho alt">ˌʌn.dɚˈpeɪd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/underpaid-us-male.mp3" data-audio-us-female="/audios/us/underpaid-us-female.mp3"></span>
-  * underestimate <span class="pho alt">ˌʌn.dɚˈes.tə.meɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/underestimate-us-male.mp3" data-audio-us-female="/audios/us/underestimate-us-female.mp3"></span>
-  * underground <span class="pho alt">ˌʌn.dɚˈɡraʊnd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/underground-us-male.mp3" data-audio-us-female="/audios/us/underground-us-female.mp3"></span>
-
-13. **super-** (above, beyond)
-  * superhuman <span class="pho alt">ˌsuː.pɚˈhjuː.mən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/superhuman-us-male.mp3" data-audio-us-female="/audios/us/superhuman-us-female.mp3"></span>
-  * supermarket <span class="pho alt">ˈsuː.pɚˌmɑːr.kɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/supermarket-us-male.mp3" data-audio-us-female="/audios/us/supermarket-us-female.mp3"></span>
-  * supervisor <span class="pho alt">ˈsuː.pɚ.vaɪ.zɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/supervisor-us-male.mp3" data-audio-us-female="/audios/us/supervisor-us-female.mp3"></span>
-
-14. **semi-** (half, partly)
-  * semicircle <span class="pho alt">ˈsem.iˌsɝː.kəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/semicircle-us-male.mp3" data-audio-us-female="/audios/us/semicircle-us-female.mp3"></span>
-  * semifinal <span class="pho alt">ˌsem.iˈfaɪ.nəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/semifinal-us-male.mp3" data-audio-us-female="/audios/us/semifinal-us-female.mp3"></span>
-  * semiconscious <span class="pho alt">ˌsem.aɪ.ˈkɑːn.ʃəs/</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/semiconscious-us-male.mp3" data-audio-us-female="/audios/us/semiconscious-us-female.mp3"></span>
-
-15. **anti-** (against)
-  * antibiotic <span class="pho alt">ˌæn.t̬i.baɪˈɑː.t̬ɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/antibiotic-us-male.mp3" data-audio-us-female="/audios/us/antibiotic-us-female.mp3"></span>
-  * antifreeze <span class="pho alt">ˈæn.t̬i.friːz</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/antifreeze-us-male.mp3" data-audio-us-female="/audios/us/antifreeze-us-female.mp3"></span>
-  * antisocial <span class="pho alt">ˌæn.t̬iˈsoʊ.ʃəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/antisocial-us-male.mp3" data-audio-us-female="/audios/us/antisocial-us-female.mp3"></span>
-
-16. **de-** (down, away from)
-  * devalue <span class="pho alt">ˌdiːˈvæl.juː</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/devalue-us-male.mp3" data-audio-us-female="/audios/us/devalue-us-female.mp3"></span>
-  * defrost <span class="pho alt">ˌdiːˈfrɑːst</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/defrost-us-male.mp3" data-audio-us-female="/audios/us/defrost-us-female.mp3"></span>
-  * decode <span class="pho alt">diːˈkoʊd</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/decode-us-male.mp3" data-audio-us-female="/audios/us/decode-us-female.mp3"></span>
-
-17. **en-** (make, put into)
-  * enable <span class="pho alt">ɪˈneɪ.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/enable-us-male.mp3" data-audio-us-female="/audios/us/enable-us-female.mp3"></span>
-  * enrich <span class="pho alt">ɪnˈrɪtʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/enrich-us-male.mp3" data-audio-us-female="/audios/us/enrich-us-female.mp3"></span>
-  * encourage <span class="pho alt">ɪnˈkɝː.ɪdʒ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/encourage-us-male.mp3" data-audio-us-female="/audios/us/encourage-us-female.mp3"></span>
-
-18. **em-** (cause to)
-  * empower <span class="pho alt">-ˈpaʊr</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/empower-us-male.mp3" data-audio-us-female="/audios/us/empower-us-female.mp3"></span>
-  * embrace <span class="pho alt">ɪmˈbreɪs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/embrace-us-male.mp3" data-audio-us-female="/audios/us/embrace-us-female.mp3"></span>
-  * employ <span class="pho alt">ɪmˈplɔɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/employ-us-male.mp3" data-audio-us-female="/audios/us/employ-us-female.mp3"></span>
-
-19. **non-** (not)
-  * nonexistent <span class="pho alt">ˌnɑn·ɪɡˈzɪs·tənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/nonexistent-us-male.mp3" data-audio-us-female="/audios/us/nonexistent-us-female.mp3"></span>
-  * nonsense <span class="pho alt">ˈnɑːn.sens</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/nonsense-us-male.mp3" data-audio-us-female="/audios/us/nonsense-us-female.mp3"></span>
-  * nonprofit <span class="pho alt">nɑnˈprɑf·ɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/nonprofit-us-male.mp3" data-audio-us-female="/audios/us/nonprofit-us-female.mp3"></span>
-
-20. **mid-** (middle)
-  * midnight <span class="pho alt">ˈmɪd.naɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/midnight-us-male.mp3" data-audio-us-female="/audios/us/midnight-us-female.mp3"></span>
-  * midterm <span class="pho alt">ˈmɪd.tɝːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/midterm-us-male.mp3" data-audio-us-female="/audios/us/midterm-us-female.mp3"></span>
-  * midfield <span class="pho alt">ˈmɪd.fiːld</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/midfield-us-male.mp3" data-audio-us-female="/audios/us/midfield-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/4.3.2-suffixes.md b/1000-hours/sounds-of-american-english-old/4.3.2-suffixes.md
deleted file mode 100644
index 98b305e4..00000000
--- a/1000-hours/sounds-of-american-english-old/4.3.2-suffixes.md
+++ /dev/null
@@ -1,101 +0,0 @@
-# 4.3.2. 常见后缀（Common Suffixes）
-
-1. **-able** (capable of)
-  * readable <span class="pho alt">ˈriː.də.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/readable-us-male.mp3" data-audio-us-female="/audios/us/readable-us-female.mp3"></span>
-  * manageable <span class="pho alt">ˈmæn.ə.dʒə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/manageable-us-male.mp3" data-audio-us-female="/audios/us/manageable-us-female.mp3"></span>
-  * comfortable <span class="pho alt">ˈkʌm.fɚ.t̬ə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/comfortable-us-male.mp3" data-audio-us-female="/audios/us/comfortable-us-female.mp3"></span>
-
-2. **-ible** (capable of)
-  * visible <span class="pho alt">ˈvɪz.ə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/visible-us-male.mp3" data-audio-us-female="/audios/us/visible-us-female.mp3"></span>
-  * flexible <span class="pho alt">ˈflek.sə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/flexible-us-male.mp3" data-audio-us-female="/audios/us/flexible-us-female.mp3"></span>
-  * edible <span class="pho alt">ˈed.ə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/edible-us-male.mp3" data-audio-us-female="/audios/us/edible-us-female.mp3"></span>
-
-3. **-al** (relating to)
-  * natural <span class="pho alt">ˈnætʃ.ɚ.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/natural-us-male.mp3" data-audio-us-female="/audios/us/natural-us-female.mp3"></span>
-  * musical <span class="pho alt">ˈmjuː.zɪ.kəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/musical-us-male.mp3" data-audio-us-female="/audios/us/musical-us-female.mp3"></span>
-  * personal <span class="pho alt">ˈpɝː.sən.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/personal-us-male.mp3" data-audio-us-female="/audios/us/personal-us-female.mp3"></span>
-
-4. **-ful** (full of)
-  * helpful <span class="pho alt">ˈhelp.fəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/helpful-us-male.mp3" data-audio-us-female="/audios/us/helpful-us-female.mp3"></span>
-  * joyful <span class="pho alt">ˈdʒɔɪ.fəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/joyful-us-male.mp3" data-audio-us-female="/audios/us/joyful-us-female.mp3"></span>
-  * careful <span class="pho alt">ˈker.fəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/careful-us-male.mp3" data-audio-us-female="/audios/us/careful-us-female.mp3"></span>
-
-5. **-less** (without)
-  * hopeless <span class="pho alt">ˈhoʊp.ləs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/hopeless-us-male.mp3" data-audio-us-female="/audios/us/hopeless-us-female.mp3"></span>
-  * fearless <span class="pho alt">ˈfɪr.ləs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/fearless-us-male.mp3" data-audio-us-female="/audios/us/fearless-us-female.mp3"></span>
-  * endless <span class="pho alt">ˈend.ləs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/endless-us-male.mp3" data-audio-us-female="/audios/us/endless-us-female.mp3"></span>
-
-6. **-ly** (in the manner of)
-  * quickly <span class="pho alt">ˈkwɪk.li</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/quickly-us-male.mp3" data-audio-us-female="/audios/us/quickly-us-female.mp3"></span>
-  * slowly <span class="pho alt">ˈsloʊ.li</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/slowly-us-male.mp3" data-audio-us-female="/audios/us/slowly-us-female.mp3"></span>
-  * happily <span class="pho alt">ˈhæp.əl.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/happily-us-male.mp3" data-audio-us-female="/audios/us/happily-us-female.mp3"></span>
-
-7. **-ment** (action or process)
-  * development <span class="pho alt">dɪˈvel.əp.mənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/development-us-male.mp3" data-audio-us-female="/audios/us/development-us-female.mp3"></span>
-  * agreement <span class="pho alt">əˈɡriː.mənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/agreement-us-male.mp3" data-audio-us-female="/audios/us/agreement-us-female.mp3"></span>
-  * improvement <span class="pho alt">ɪmˈpruːv.mənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/improvement-us-male.mp3" data-audio-us-female="/audios/us/improvement-us-female.mp3"></span>
-
-8. **-ness** (state or quality)
-  * kindness <span class="pho alt">ˈkaɪnd.nəs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/kindness-us-male.mp3" data-audio-us-female="/audios/us/kindness-us-female.mp3"></span>
-  * darkness <span class="pho alt">ˈdɑːrk.nəs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/darkness-us-male.mp3" data-audio-us-female="/audios/us/darkness-us-female.mp3"></span>
-  * happiness <span class="pho alt">ˈhæp.i.nəs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/happiness-us-male.mp3" data-audio-us-female="/audios/us/happiness-us-female.mp3"></span>
-
-9. **-er** (one who, comparative)
-  * teacher <span class="pho alt">ˈtiː.tʃɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/teacher-us-male.mp3" data-audio-us-female="/audios/us/teacher-us-female.mp3"></span>
-  * runner <span class="pho alt">ˈrʌn.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/runner-us-male.mp3" data-audio-us-female="/audios/us/runner-us-female.mp3"></span>
-  * faster <span class="pho alt">fæst</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/faster-us-male.mp3" data-audio-us-female="/audios/us/faster-us-female.mp3"></span>
-
-10. **-or** (one who)
-  * actor <span class="pho alt">ˈæk.tɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/actor-us-male.mp3" data-audio-us-female="/audios/us/actor-us-female.mp3"></span>
-  * inventor <span class="pho alt">ɪnˈven.t̬ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/inventor-us-male.mp3" data-audio-us-female="/audios/us/inventor-us-female.mp3"></span>
-  * conductor <span class="pho alt">kənˈdʌk.tɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/conductor-us-male.mp3" data-audio-us-female="/audios/us/conductor-us-female.mp3"></span>
-
-11. **-ist** (one who practices)
-  * artist <span class="pho alt">ˈɑːr.t̬ɪst</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/artist-us-male.mp3" data-audio-us-female="/audios/us/artist-us-female.mp3"></span>
-  * scientist <span class="pho alt">ˈsaɪən.tɪst</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/scientist-us-male.mp3" data-audio-us-female="/audios/us/scientist-us-female.mp3"></span>
-  * pianist <span class="pho alt">ˈpiː.ən.ɪst</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pianist-us-male.mp3" data-audio-us-female="/audios/us/pianist-us-female.mp3"></span>
-
-12. **-ion** (action or condition)
-  * celebration <span class="pho alt">ˌsel.əˈbreɪ.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/celebration-us-male.mp3" data-audio-us-female="/audios/us/celebration-us-female.mp3"></span>
-  * decision <span class="pho alt">dɪˈsɪʒ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/decision-us-male.mp3" data-audio-us-female="/audios/us/decision-us-female.mp3"></span>
-  * creation <span class="pho alt">kriˈeɪ.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/creation-us-male.mp3" data-audio-us-female="/audios/us/creation-us-female.mp3"></span>
-
-13. **-tion** (action or condition)
-  * education <span class="pho alt">ˌedʒ.əˈkeɪ.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/education-us-male.mp3" data-audio-us-female="/audios/us/education-us-female.mp3"></span>
-  * suggestion <span class="pho alt">səˈdʒes.tʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/suggestion-us-male.mp3" data-audio-us-female="/audios/us/suggestion-us-female.mp3"></span>
-  * transportation <span class="pho alt">ˌtræn.spɚˈteɪ.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/transportation-us-male.mp3" data-audio-us-female="/audios/us/transportation-us-female.mp3"></span>
-
-14. **-sion** (state or condition)
-  * admission <span class="pho alt">ədˈmɪʃ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/admission-us-male.mp3" data-audio-us-female="/audios/us/admission-us-female.mp3"></span>
-  * confusion <span class="pho alt">kənˈfjuː.ʒən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/confusion-us-male.mp3" data-audio-us-female="/audios/us/confusion-us-female.mp3"></span>
-  * extension <span class="pho alt">ɪkˈsten.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/extension-us-male.mp3" data-audio-us-female="/audios/us/extension-us-female.mp3"></span>
-
-15. **-ous** (full of)
-  * dangerous <span class="pho alt">ˈdeɪn.dʒɚ.əs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/dangerous-us-male.mp3" data-audio-us-female="/audios/us/dangerous-us-female.mp3"></span>
-  * nervous <span class="pho alt">ˈnɝː.vəs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/nervous-us-male.mp3" data-audio-us-female="/audios/us/nervous-us-female.mp3"></span>
-  * famous <span class="pho alt">ˈfeɪ.məs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/famous-us-male.mp3" data-audio-us-female="/audios/us/famous-us-female.mp3"></span>
-
-16. **-ive** (tending to)
-  * active <span class="pho alt">ˈæk.tɪv</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/active-us-male.mp3" data-audio-us-female="/audios/us/active-us-female.mp3"></span>
-  * creative <span class="pho alt">kriˈeɪ.t̬ɪv</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/creative-us-male.mp3" data-audio-us-female="/audios/us/creative-us-female.mp3"></span>
-  * attractive <span class="pho alt">əˈtræk.tɪv</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/attractive-us-male.mp3" data-audio-us-female="/audios/us/attractive-us-female.mp3"></span>
-
-17. **-ic** (relating to)
-  * artistic <span class="pho alt">ɑːrˈtɪs.tɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/artistic-us-male.mp3" data-audio-us-female="/audios/us/artistic-us-female.mp3"></span>
-  * athletic <span class="pho alt">æθˈlet̬.ɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/athletic-us-male.mp3" data-audio-us-female="/audios/us/athletic-us-female.mp3"></span>
-  * energetic <span class="pho alt">ˌen.ɚˈdʒet̬.ɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/energetic-us-male.mp3" data-audio-us-female="/audios/us/energetic-us-female.mp3"></span>
-
-18. **-ity** (state or quality)
-  * reality <span class="pho alt">riˈæl.ə.t̬i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/reality-us-male.mp3" data-audio-us-female="/audios/us/reality-us-female.mp3"></span>
-  * ability <span class="pho alt">əˈbɪl.ə.t̬i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/ability-us-male.mp3" data-audio-us-female="/audios/us/ability-us-female.mp3"></span>
-  * simplicity <span class="pho alt">sɪmˈplɪs.ə.t̬i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/simplicity-us-male.mp3" data-audio-us-female="/audios/us/simplicity-us-female.mp3"></span>
-
-19. **-ance** (state or quality)
-  * performance <span class="pho alt">pɚˈfɔːr.məns</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/performance-us-male.mp3" data-audio-us-female="/audios/us/performance-us-female.mp3"></span>
-  * importance <span class="pho alt">ɪmˈpɔːr.təns</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/importance-us-male.mp3" data-audio-us-female="/audios/us/importance-us-female.mp3"></span>
-  * acceptance <span class="pho alt">əkˈsep.təns</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/acceptance-us-male.mp3" data-audio-us-female="/audios/us/acceptance-us-female.mp3"></span>
-
-20. **-ence** (state or quality)
-  * difference <span class="pho alt">ˈdɪf.ɚ.əns</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/difference-us-male.mp3" data-audio-us-female="/audios/us/difference-us-female.mp3"></span>
-  * independence <span class="pho alt">ˌɪn.dɪˈpen.dəns</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/independence-us-male.mp3" data-audio-us-female="/audios/us/independence-us-female.mp3"></span>
-  * existence <span class="pho alt">ɪɡˈzɪs.təns</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/existence-us-male.mp3" data-audio-us-female="/audios/us/existence-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/4.3.3-roots.md b/1000-hours/sounds-of-american-english-old/4.3.3-roots.md
deleted file mode 100644
index a4f783cd..00000000
--- a/1000-hours/sounds-of-american-english-old/4.3.3-roots.md
+++ /dev/null
@@ -1,126 +0,0 @@
-# 4.3.3. 常见词根（Common Roots）
-
-1. **aqua** (water)
-  * aquarium <span class="pho alt">əˈkwer.i.əm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/aquarium-us-male.mp3" data-audio-us-female="/audios/us/aquarium-us-female.mp3"></span>
-  * aquatic <span class="pho alt">əˈkwæt̬.ɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/aquatic-us-male.mp3" data-audio-us-female="/audios/us/aquatic-us-female.mp3"></span>
-  * aqueduct <span class="pho alt">ˈæk.wə.dʌkt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/aqueduct-us-male.mp3" data-audio-us-female="/audios/us/aqueduct-us-female.mp3"></span>
-
-2. **aud** (hear)
-  * audience <span class="pho alt">ˈɑː.di.əns</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/audience-us-male.mp3" data-audio-us-female="/audios/us/audience-us-female.mp3"></span>
-  * audio <span class="pho alt">ˈɑː.di.oʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/audio-us-male.mp3" data-audio-us-female="/audios/us/audio-us-female.mp3"></span>
-  * audition <span class="pho alt">ɑːˈdɪʃ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/audition-us-male.mp3" data-audio-us-female="/audios/us/audition-us-female.mp3"></span>
-
-3. **bene** (good, well)
-  * benefit <span class="pho alt">ˈben.ə.fɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/benefit-us-male.mp3" data-audio-us-female="/audios/us/benefit-us-female.mp3"></span>
-  * benevolent <span class="pho alt">bəˈnev.əl.ənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/benevolent-us-male.mp3" data-audio-us-female="/audios/us/benevolent-us-female.mp3"></span>
-  * benefactor <span class="pho alt">ˈben.ə.fæk.tɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/benefactor-us-male.mp3" data-audio-us-female="/audios/us/benefactor-us-female.mp3"></span>
-
-4. **cent** (hundred)
-  * century <span class="pho alt">ˈsen.tʃər.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/century-us-male.mp3" data-audio-us-female="/audios/us/century-us-female.mp3"></span>
-  * percent <span class="pho alt">pɚˈsent</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/percent-us-male.mp3" data-audio-us-female="/audios/us/percent-us-female.mp3"></span>
-  * centennial <span class="pho alt">senˈten.i.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/centennial-us-male.mp3" data-audio-us-female="/audios/us/centennial-us-female.mp3"></span>
-
-5. **dict** (say, speak)
-  * dictionary <span class="pho alt">ˈdɪk.ʃən.er.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/dictionary-us-male.mp3" data-audio-us-female="/audios/us/dictionary-us-female.mp3"></span>
-  * predict <span class="pho alt">prɪˈdɪkt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/predict-us-male.mp3" data-audio-us-female="/audios/us/predict-us-female.mp3"></span>
-  * dictate <span class="pho alt">ˈdɪk.teɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/dictate-us-male.mp3" data-audio-us-female="/audios/us/dictate-us-female.mp3"></span>
-
-6. **duc** (lead)
-  * conduct <span class="pho alt">kənˈdʌkt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/conduct-us-male.mp3" data-audio-us-female="/audios/us/conduct-us-female.mp3"></span>
-  * produce <span class="pho alt">prəˈduːs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/produce-us-male.mp3" data-audio-us-female="/audios/us/produce-us-female.mp3"></span>
-  * reduce <span class="pho alt">rɪˈduːs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/reduce-us-male.mp3" data-audio-us-female="/audios/us/reduce-us-female.mp3"></span>
-
-7. **fract** (break)
-  * fracture <span class="pho alt">ˈfræk.tʃɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/fracture-us-male.mp3" data-audio-us-female="/audios/us/fracture-us-female.mp3"></span>
-  * fraction <span class="pho alt">ˈfræk.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/fraction-us-male.mp3" data-audio-us-female="/audios/us/fraction-us-female.mp3"></span>
-  * infraction <span class="pho alt">ɪnˈfræk.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/infraction-us-male.mp3" data-audio-us-female="/audios/us/infraction-us-female.mp3"></span>
-
-8. **ject** (throw)
-  * project <span class="pho alt">ˈprɑː.dʒekt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/project-us-male.mp3" data-audio-us-female="/audios/us/project-us-female.mp3"></span>
-  * inject <span class="pho alt">ɪnˈdʒekt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/inject-us-male.mp3" data-audio-us-female="/audios/us/inject-us-female.mp3"></span>
-  * reject <span class="pho alt">rɪˈdʒekt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/reject-us-male.mp3" data-audio-us-female="/audios/us/reject-us-female.mp3"></span>
-
-9. **jud** (judge)
-  * judicial <span class="pho alt">dʒuːˈdɪʃ.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/judicial-us-male.mp3" data-audio-us-female="/audios/us/judicial-us-female.mp3"></span>
-  * prejudice <span class="pho alt">ˈpredʒ.ə.dɪs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/prejudice-us-male.mp3" data-audio-us-female="/audios/us/prejudice-us-female.mp3"></span>
-  * judgment <span class="pho alt">ˈdʒʌdʒ.mənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/judgment-us-male.mp3" data-audio-us-female="/audios/us/judgment-us-female.mp3"></span>
-
-10. **mal** (bad, ill)
-  * malnutrition <span class="pho alt">ˌmæl.nuːˈtrɪʃ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/malnutrition-us-male.mp3" data-audio-us-female="/audios/us/malnutrition-us-female.mp3"></span>
-  * malicious <span class="pho alt">məˈlɪʃ.əs</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/malicious-us-male.mp3" data-audio-us-female="/audios/us/malicious-us-female.mp3"></span>
-  * malfunction <span class="pho alt">ˌmælˈfʌŋk.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/malfunction-us-male.mp3" data-audio-us-female="/audios/us/malfunction-us-female.mp3"></span>
-
-11. **mater** (mother)
-  * maternal <span class="pho alt">məˈtɝː.nəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/maternal-us-male.mp3" data-audio-us-female="/audios/us/maternal-us-female.mp3"></span>
-  * maternity <span class="pho alt">məˈtɝː.nə.t̬i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/maternity-us-male.mp3" data-audio-us-female="/audios/us/maternity-us-female.mp3"></span>
-  * matriarch <span class="pho alt">ˈmeɪ.tri.ɑːrk</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/matriarch-us-male.mp3" data-audio-us-female="/audios/us/matriarch-us-female.mp3"></span>
-
-12. **mit** (send)
-  * transmit <span class="pho alt">trænsˈmɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/transmit-us-male.mp3" data-audio-us-female="/audios/us/transmit-us-female.mp3"></span>
-  * admit <span class="pho alt">ədˈmɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/admit-us-male.mp3" data-audio-us-female="/audios/us/admit-us-female.mp3"></span>
-  * submit <span class="pho alt">səbˈmɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/submit-us-male.mp3" data-audio-us-female="/audios/us/submit-us-female.mp3"></span>
-
-13. **mort** (death)
-  * mortal <span class="pho alt">ˈmɔːr.t̬əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/mortal-us-male.mp3" data-audio-us-female="/audios/us/mortal-us-female.mp3"></span>
-  * mortician <span class="pho alt">mɔːrˈtɪʃ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/mortician-us-male.mp3" data-audio-us-female="/audios/us/mortician-us-female.mp3"></span>
-  * mortify <span class="pho alt">ˈmɔːr.t̬ə.faɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/mortify-us-male.mp3" data-audio-us-female="/audios/us/mortify-us-female.mp3"></span>
-
-14. **multi** (many)
-  * multiple <span class="pho alt">ˈmʌl.tə.pəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/multiple-us-male.mp3" data-audio-us-female="/audios/us/multiple-us-female.mp3"></span>
-  * multiply <span class="pho alt">ˈmʌl.tə.plaɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/multiply-us-male.mp3" data-audio-us-female="/audios/us/multiply-us-female.mp3"></span>
-  * multinational <span class="pho alt">ˌmʌl.t̬iˈnæʃ.ən.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/multinational-us-male.mp3" data-audio-us-female="/audios/us/multinational-us-female.mp3"></span>
-
-15. **pend** (hang, weigh)
-  * pendant <span class="pho alt">ˈpen.dənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/pendant-us-male.mp3" data-audio-us-female="/audios/us/pendant-us-female.mp3"></span>
-  * suspend <span class="pho alt">səˈspend</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/suspend-us-male.mp3" data-audio-us-female="/audios/us/suspend-us-female.mp3"></span>
-  * depend <span class="pho alt">dɪˈpend</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/depend-us-male.mp3" data-audio-us-female="/audios/us/depend-us-female.mp3"></span>
-
-16. **port** (carry)
-  * transport <span class="pho alt">ˈtræn.spɔːrt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/transport-us-male.mp3" data-audio-us-female="/audios/us/transport-us-female.mp3"></span>
-  * export <span class="pho alt">ˈek.spɔːrt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/export-us-male.mp3" data-audio-us-female="/audios/us/export-us-female.mp3"></span>
-  * import <span class="pho alt">ˈɪm.pɔːrt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/import-us-male.mp3" data-audio-us-female="/audios/us/import-us-female.mp3"></span>
-
-17. **scrib/script** (write)
-  * describe <span class="pho alt">dɪˈskraɪb</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/describe-us-male.mp3" data-audio-us-female="/audios/us/describe-us-female.mp3"></span>
-  * manuscript <span class="pho alt">ˈmæn.jə.skrɪpt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/manuscript-us-male.mp3" data-audio-us-female="/audios/us/manuscript-us-female.mp3"></span>
-  * subscription <span class="pho alt">səbˈskrɪp.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/subscription-us-male.mp3" data-audio-us-female="/audios/us/subscription-us-female.mp3"></span>
-
-18. **sect/sec** (cut)
-  * section <span class="pho alt">ˈsek.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/section-us-male.mp3" data-audio-us-female="/audios/us/section-us-female.mp3"></span>
-  * dissect <span class="pho alt">daɪˈsekt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/dissect-us-male.mp3" data-audio-us-female="/audios/us/dissect-us-female.mp3"></span>
-  * intersect <span class="pho alt">ˌɪn.t̬ɚˈsekt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/intersect-us-male.mp3" data-audio-us-female="/audios/us/intersect-us-female.mp3"></span>
-
-19. **sent/sens** (feel)
-  * sensation <span class="pho alt">senˈseɪ.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sensation-us-male.mp3" data-audio-us-female="/audios/us/sensation-us-female.mp3"></span>
-  * sensitive <span class="pho alt">ˈsen.sə.t̬ɪv</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/sensitive-us-male.mp3" data-audio-us-female="/audios/us/sensitive-us-female.mp3"></span>
-  * consent <span class="pho alt">kənˈsent</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/consent-us-male.mp3" data-audio-us-female="/audios/us/consent-us-female.mp3"></span>
-
-20. **spec/spect** (look)
-  * inspect <span class="pho alt">ɪnˈspekt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/inspect-us-male.mp3" data-audio-us-female="/audios/us/inspect-us-female.mp3"></span>
-  * spectator <span class="pho alt">spekˈteɪ.t̬ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/spectator-us-male.mp3" data-audio-us-female="/audios/us/spectator-us-female.mp3"></span>
-  * spectacle <span class="pho alt">ˈspek.tə.kəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/spectacle-us-male.mp3" data-audio-us-female="/audios/us/spectacle-us-female.mp3"></span>
-
-21. **struct** (build)
-  * construct <span class="pho alt">kənˈstrʌkt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/construct-us-male.mp3" data-audio-us-female="/audios/us/construct-us-female.mp3"></span>
-  * structure <span class="pho alt">ˈstrʌk.tʃɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/structure-us-male.mp3" data-audio-us-female="/audios/us/structure-us-female.mp3"></span>
-  * destruct <span class="pho alt">ˌself.dɪˈstrʌkt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/destruct-us-male.mp3" data-audio-us-female="/audios/us/destruct-us-female.mp3"></span>
-
-22. **tele** (far)
-  * telephone <span class="pho alt">ˈtel.ə.foʊn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/telephone-us-male.mp3" data-audio-us-female="/audios/us/telephone-us-female.mp3"></span>
-  * television <span class="pho alt">ˈtel.ə.vɪʒ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/television-us-male.mp3" data-audio-us-female="/audios/us/television-us-female.mp3"></span>
-  * telegraph <span class="pho alt">ˈtel.ə.ɡræf</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/telegraph-us-male.mp3" data-audio-us-female="/audios/us/telegraph-us-female.mp3"></span>
-
-23. **terra** (earth)
-  * terrestrial <span class="pho alt">təˈres.tri.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/terrestrial-us-male.mp3" data-audio-us-female="/audios/us/terrestrial-us-female.mp3"></span>
-  * territory <span class="pho alt">ˈter.ə.tɔːr.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/territory-us-male.mp3" data-audio-us-female="/audios/us/territory-us-female.mp3"></span>
-  * terrain <span class="pho alt">təˈreɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/terrain-us-male.mp3" data-audio-us-female="/audios/us/terrain-us-female.mp3"></span>
-
-24. **vac** (empty)
-  * vacant <span class="pho alt">ˈveɪ.kənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/vacant-us-male.mp3" data-audio-us-female="/audios/us/vacant-us-female.mp3"></span>
-  * vacuum <span class="pho alt">ˈvæk.juːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/vacuum-us-male.mp3" data-audio-us-female="/audios/us/vacuum-us-female.mp3"></span>
-  * evacuate <span class="pho alt">ɪˈvæk.ju.eɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/evacuate-us-male.mp3" data-audio-us-female="/audios/us/evacuate-us-female.mp3"></span>
-
-25. **vid/vis** (see)
-  * video <span class="pho alt">ˈvɪd.i.oʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/video-us-male.mp3" data-audio-us-female="/audios/us/video-us-female.mp3"></span>
-  * vision <span class="pho alt">ˈvɪʒ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/vision-us-male.mp3" data-audio-us-female="/audios/us/vision-us-female.mp3"></span>
-  * invisible <span class="pho alt">ɪnˈvɪz.ə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/us/invisible-us-male.mp3" data-audio-us-female="/audios/us/invisible-us-female.mp3"></span>
diff --git a/1000-hours/sounds-of-american-english-old/5-sumup.md b/1000-hours/sounds-of-american-english-old/5-sumup.md
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-
-# 5. 总结（Sum up）
-
-其实，读音与拼写，就是学英语的 “最少必要知识” 了。所谓的 “最少必要知识”，指的是那些实际上很少很少，却可以做到 “只要掌握了之后就可以开始有资格有资本自顾自前行” 的知识。
-
-Actually, pronunciation and spelling are the "minimum necessary knowledge" for learning English. "Minimum necessary knowledge" refers to the very basic yet crucial information that, once mastered, allows you to move forward independently.
-
-练好了正确发音，掌握了基本的拼写，接下来就可以直接用英语了。尤其是在人工智能已经在语言学习方面超越了所有英语老师甚至英语词典和语法书的今天。有什么不懂的，有什么不会的，直接问人工智能就可以了。它的答案一定是最好的（尤其是在英语方面），剩下的，只有一件事，用。在用的过程中练，在练的过程中用。
-
-If you get your pronunciation right and learn basic spelling, you can start *using* English *right away*. This is especially true today when artificial intelligence has surpassed all English teachers, dictionaries, and grammar books in language learning. Whenever there's something you don't understand, you can just ask AI. Its answers, particularly for English, will be the best. After that, there's only one thing left to do: *practice*. *Use* English in practice and *practice* while using it.
-
-祝你好运！
-
-Good luck!
diff --git a/1000-hours/sounds-of-american-english-old/draft.md b/1000-hours/sounds-of-american-english-old/draft.md
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-# Drafts
-
-辅音 <span class="pho">t</span> 在美式英语中有个弹舌音变体，<span class="pho">t̬</span>，例如，*cutting* <span class="pho alt">ˈkʌt̬ɪŋ</span>。
-
-The consonant <span class="pho">t</span> has a flapping variant, <span class="pho">t̬</span>, as in the word *cutting*, pronounced <span class="pho alt">ˈkʌt̬ɪŋ</span>.
-
-辅音 <span class="pho">l</span> 是音节辅音（[2.2.14](2.2.14-lr)），有时会在之前自然附带一个 <span class="pho">ə</span> 音，可能被标注为 <span class="pho">əl</span>、<span class="pho">ᵊl</span>（上标式 <span class="pho">ə</span>） 或者 <span class="pho">l̩</span>（注意 <span class="pho">l</span> 下的那根小竖线）。
-
-The consonant <span class="pho">l</span> is a syllabic consonant ([2.2.14](2.2.14-lr)), which sometimes naturally comes with an <span class="pho">ə</span> sound before it. This may be annotated as <span class="pho">əl</span>, <span class="pho">ᵊl</span> (with a superscript <span class="pho">ə</span>), or <span class="pho">l̩</span> (note the small vertical line underneath the <span class="pho">l</span>).
-
-6 个基础元音中，<span class="pho">ə</span> 和 <span class="pho">ɪ</span> 有相对更多的变体（*allophone*）：
-In the 6 basic vowels, <span class="pho">ə</span> and <span class="pho">ɪ</span> have relatively more variants, or *allophones*:
-
-* <span class="pho">ɪ</span>：
-  * 除了长元音版本 <span class="pho">iː</span> 之外，还有一个半长版本 <span class="pho">i</span>，例如 *happy* <span class="pho alt">ˈhæpi</span>[^1]；
-  * In addition to the long vowel version <span class="pho">i</span>ː, there's also a semi-long version <span class="pho">i</span>, as in *happy* <span class="pho alt">ˈhæpi</span>.
-* <span class="pho">ə</span>：
-  * 长元音版本 <span class="pho">əː</span> 在 CEPD[^2] 中被标注为 <span class="pho">ɜː</span>，例如 *bird* <span class="pho alt">bɜːd</span> (UK)
-  * The long vowel version <span class="pho">əː</span> is annotated as <span class="pho">ɜː</span> in the CEPD[^2], like in *bird* <span class="pho alt">bɜːd</span> (UK).
-  * 儿化的短元音 <span class="pho">ə</span> 被标注为 <span class="pho">ɚ</span>，例如 *mother* <span class="pho alt">ˈmʌðɚ</span>；
-  * The rhotacized short vowel <span class="pho">ə</span> is annotated as <span class="pho">ɚ</span>, as in *mother* pronounced <span class="pho alt">ˈmʌðɚ</span>.
-  * 儿化的长元音 <span class="pho">əː</span> 被标注为 <span class="pho">ɝː</span> 例如 *bird* <span class="pho alt">bɝːd</span> (US)
-  * The rhotacized long vowel <span class="pho">əː</span> is annotated as <span class="pho">ɝː</span>, like in *bird* pronounced <span class="pho alt">bɝːd</span> (US).
-
-英式英语中的 <span class="pho">eə</span>、<span class="pho">ɪə</span>、<span class="pho">ʊə</span>，在美式英语中的发音末尾都有儿化音，因此被标注为：<span class="pho">er</span>、<span class="pho">ɪr</span>、<span class="pho">ʊr</span>。
-
-The sounds represented by <span class="pho">eə</span>, <span class="pho">ɪə</span>, and <span class="pho">ʊə</span> in British English are rhotacized in American English, which is why they are notated as: <span class="pho">er</span>, <span class="pho">ɪr</span>, <span class="pho">ʊr</span>.
-
-另外，英式英语中还有两个三元音: <span class="pho">aɪə</span> 比如，*fire* <span class="pho alt">faɪə</span>；*hour* <span class="pho alt">aʊə</span>。在美式英语中，这两个三元音被简化为两个双元音的更为明显的儿化音，<span class="pho">aɪə</span> → <span class="pho">aɪr</span>，比如，*fire* <span class="pho alt">faɪr</span>, *hour* <span class="pho alt">aʊr</span>。
-
-Furthermore, in British English, there are two triphthongs: <span class="pho">aɪə</span> as in *fire* pronounced <span class="pho alt">faɪə</span> and <span class="pho">aʊə</span> as in *hour* pronounced <span class="pho alt">aʊə</span>. In American English, these two triphthongs simplify into more apparent rhotacized diphthongs, <span class="pho">aɪə</span> → <span class="pho">aɪr</span>, for example, *fire* pronounced <span class="pho alt">faɪr</span>, and *hour* pronounced <span class="pho alt">aʊr</span>.
-
-[^1]: The middle dot `<span class="pho"> in </span>/ˈhæpi/<span class="pho"> is an annotation of syllable division. A dot </span>.` is used in CEPD, but for clearer html rendering, we use a raised one here.
-[^2]: CEPD, Cambridge English Pronunciation Dictionary, https://dictionary.cambridge.org/help/phonetics.html.
-
-
-
-比较幸运的是，大多数的音标标注差异集中在**元音**标记上，尤其是美式英语的元音 —— 所以也不算是太难掌握。
-
-Luckily, the majority of phonetic notation differences are concentrated in *vowel* markings, especially American vowels, which makes it somewhat easier to master.
-
-关于美式发音的音标标注，可以大致总结为以下几点：
-
-Here are some key points to take note of when it comes to phonetic representation of American English:
-
-> - 短元音 <span class="pho">ʌ</span> 变得与 <span class="pho">ə</span> 非常接近，甚至常常直接被 <span class="pho">ə</span> 替代。比如，*but* <span class="pho alt">bʌt</span> 可能直接被标注为 <span class="pho alt">bət</span>。
-> - The short vowel <span class="pho">ʌ</span> often sounds very similar to <span class="pho">ə</span> and is frequently replaced by it in transcription. For example, *but* <span class="pho alt">bʌt</span> would be transcribed as <span class="pho alt">bət</span>.
-> - 长短元音不统一使用 <span class="pho">ː</span> 区分，而是<span class="pho">ə/ɑ</span>、<span class="pho">ə/ɜ</span>、<span class="pho">ɚ/ɝ</span>、 <span class="pho">e/æ</span>、<span class="pho">ɪ/i</span>、<span class="pho">ʊ/u</span>、<span class="pho">ɒ/ɔ</span>。
-> - Long and short vowels are differentiated not by using <span class="pho">ː</span>, but by pairs such as <span class="pho">ə/ɑ</span>, <span class="pho">ə/ɜ</span>, <span class="pho">ɚ/ɝ</span>, <span class="pho">e/æ</span>, <span class="pho">ɪ/i</span>, <span class="pho">ʊ/u</span>, <span class="pho">ɒ/ɔ</span>.
-> - 短元音 <span class="pho">e</span> 有时用 <span class="pho">ɛ</span> 标注。
-> - The short vowel <span class="pho">e</span> is sometimes transcribed as <span class="pho">ɛ</span>.
-> - 短元音 <span class="pho">ə</span> ，由于经常附带着 <span class="pho">ʳ</span> 音，常常被标注为 <span class="pho">ɚ</span>；不带有 <span class="pho">ʳ</span> 音的时候，常常被标注为 <span class="pho">ɜ</span>。
-> - The short vowel <span class="pho">ə</span>, often accompanied by the rhotic <span class="pho">ʳ</span>, is commonly transcribed as <span class="pho">ɚ</span>. When the rhotic sound is absent, <span class="pho">ə</span> is often transcribed as <span class="pho">ɜ</span>.
-> - 长元音 <span class="pho">əː</span>，同样由于经常附带着 <span class="pho">ʳ</span> 音，常常被标注为 <span class="pho">ɝ</span>。
-> - The long vowel <span class="pho">əː</span>, due to its frequent association with <span class="pho">ʳ</span>, is generally transcribed as <span class="pho">ɝ</span>.
-> - <span class="pho">ə</span> 结尾的双元音，都用 <span class="pho">r</span>：<span class="pho">ɪə</span> ⭢ <span class="pho">ɪr</span>，<span class="pho">eə</span> ⭢ <span class="pho">er</span>，<span class="pho">ʊə</span> ⭢ <span class="pho">ʊr</span>。
-> - Diphthongs ending in <span class="pho">ə</span> are represented with <span class="pho">r</span>: <span class="pho">ɪə</span> becomes <span class="pho">ɪr</span>, <span class="pho">eə</span> becomes <span class="pho">er</span>, <span class="pho">ʊə</span> becomes <span class="pho">ʊr</span>.
-> - 非重音音节中的 <span class="pho">ɪ</span> 可能会被标注为 <span class="pho">ə</span>。
-> - The <span class="pho">ɪ</span> in unstressed syllables may be transcribed as <span class="pho">ə</span>.
-> - 短元音 <span class="pho">ɒ</span> 在美式发音中读作 <span class="pho">ɑ</span>，也如此标注，比如，*hot* <span class="pho alt">hɑt</span> —— <span class="pho">ɑ</span> 比 <span class="pho">ʌ/ə</span> 略长一些，比 <span class="pho">ɑr</span> 短。
-> - The short vowel <span class="pho">ɒ</span> is pronounced as <span class="pho">ɑ</span> in American English and is transcribed as such. For example, *hot* is transcribed as <span class="pho alt">hɑt</span>. <span class="pho">ɑ</span> is slightly longer than <span class="pho">ʌ/ə</span> but shorter than <span class="pho">ɑr</span>.
-> - <span class="pho">t</span> 的弹舌音用 <span class="pho">t̬</span> 标注。
-> - The flapping <span class="pho">t</span> sound in American English is represented by <span class="pho">t̬</span>.
-
-### <span class="pho">ʌ</span>
-
-*but* <span class="pho alt">bʌt</span>, *chum* <span class="pho alt">tʃʌm</span>, *cut* <span class="pho alt">kʌt</span>, *drum* <span class="pho alt">drʌm</span>, *duck* <span class="pho alt">dʌk</span>, *fun* <span class="pho alt">fʌn</span>, *gun* <span class="pho alt">ɡʌn</span>, *hut* <span class="pho alt">hʌt</span>, *jump* <span class="pho alt">dʒʌmp</span>, *luck* <span class="pho alt">lʌk</span>, *mud* <span class="pho alt">mʌd</span>, *nut* <span class="pho alt">nʌt</span>, *pup* <span class="pho alt">pʌp</span>, *run* <span class="pho alt">rʌn</span>, *shut* <span class="pho alt">ʃʌt</span>, *sun* <span class="pho alt">sʌn</span>, *thug* <span class="pho alt">θʌɡ</span>, *thus* <span class="pho alt">ðʌs</span>, *truck* <span class="pho alt">trʌk</span>, *tut* <span class="pho alt">tʌt</span>, *vulgar* <span class="pho alt">ˈvʌlɡɚ</span>, *won* <span class="pho alt">wʌn</span>, *yum*  <span class="pho alt">jʌm</span>
-
-
-### <span class="pho">e</span>
-
-*bet* <span class="pho alt">bet</span>, *check* <span class="pho alt">tʃek</span>, *desk* <span class="pho alt">desk</span>, *dress* <span class="pho alt">dres</span>, *fed* <span class="pho alt">fed</span>, *get* <span class="pho alt">ɡet</span>, *hen* <span class="pho alt">hen</span>, *jet* <span class="pho alt">dʒet</span>, *kept* <span class="pho alt">kept</span>, *let* <span class="pho alt">let</span>, *met* <span class="pho alt">met</span>, *net* <span class="pho alt">net</span>, *pet* <span class="pho alt">pet</span>, *red* <span class="pho alt">red</span>, *set* <span class="pho alt">set</span>, *shed* <span class="pho alt">ʃed</span>, *test* <span class="pho alt">test</span>, *theft* <span class="pho alt">θeft</span>, *trek* <span class="pho alt">trek</span>, *vet* <span class="pho alt">vet</span>, *wet* <span class="pho alt">wet</span>, *yet* <span class="pho alt">jet</span>, *zed* <span class="pho alt">zed</span>
-
-### <span class="pho">ə</span>
-
-*ago* <span class="pho alt">əˈɡoʊ</span>, *button* <span class="pho alt">ˈbʌt̬ən</span>, *develop* <span class="pho alt">dɪˈveləp</span>, *dramatic* <span class="pho alt">drəˈmæt̬ɪk</span>, *expression* <span class="pho alt">ɪkˈspreʃən</span>, *onion* <span class="pho alt">ˈʌnjən</span>, *realize* <span class="pho alt">ˈriːəlaɪz</span>, *standard* <span class="pho alt">ˈstændɚd</span>, *system* <span class="pho alt">ˈsɪstəm</span>, *telegram* <span class="pho alt">ˈteləɡræm</span>
-
-注意：没有儿化的 <span class="pho">ə</span> 在美式英语中，被称作 *schwa*，非重读央元音 —— 即，只出现在非重读音节中。
-
-### <span class="pho">ɚ</span>
-
-*danger* <span class="pho alt">ˈdeɪndʒɚ</span>, *freezer* <span class="pho alt">ˈfriːzɚ</span>, *harder* <span class="pho alt">hɑːrdɚ</span>, *larger* <span class="pho alt">lɑːrdʒɚ</span>, *paper* <span class="pho alt">ˈpeɪpɚ</span>, *server* <span class="pho alt">ˈsɝːvɚ</span>, *teacher* <span class="pho alt">ˈtiːtʃɚ</span>, *water* <span class="pho alt">ˈwɑːt̬ɚ</span>, *worker* <span class="pho alt">ˈwɝːkɚ</span>
-
-注意：儿化的短元音 <span class="pho">ɚ</span> 只出现在非重读音节中。
-
-### <span class="pho">ɪ</span>
-
-*bit* <span class="pho alt">bɪt</span>, *chip* <span class="pho alt">tʃɪp</span>, *did* <span class="pho alt">dɪd</span>, *drill* <span class="pho alt">drɪl</span>, *gig* <span class="pho alt">ɡɪɡ</span>, *gin* <span class="pho alt">dʒɪn</span>, *his* <span class="pho alt">hɪz</span>, *if* <span class="pho alt">ɪf</span>, *kick* <span class="pho alt">kɪk</span>, *lip* <span class="pho alt">lɪp</span>, *milk* <span class="pho alt">mɪlk</span>, *nil* <span class="pho alt">nɪl</span>, *pick* <span class="pho alt">pɪk</span>, *rip* <span class="pho alt">rɪp</span>, *ship* <span class="pho alt">ʃɪp</span>, *sit* <span class="pho alt">sɪt</span>, *thick* <span class="pho alt">θɪk</span>, *this* <span class="pho alt">ðɪs</span>, *tip* <span class="pho alt">tɪp</span>, *trick* <span class="pho alt">trɪk</span>, *vivid* <span class="pho alt">ˈvɪvɪd</span>, *wit* <span class="pho alt">wɪ</span>, *zip* <span class="pho alt">zɪp</span>
-
-### <span class="pho">ʊ</span>
-
-*book* <span class="pho alt">bʊk</span>, *cook* <span class="pho alt">kʊk</span>, *foot* <span class="pho alt">fʊt</span>, *good* <span class="pho alt">ɡʊd</span>, *put* <span class="pho alt">pʊt</span>, *should* <span class="pho alt">ʃʊd</span>, *wood* <span class="pho alt">wʊd</span>
-
-### <span class="pho">æ</span>
-
-*add* <span class="pho alt">æd</span>, *bad* <span class="pho alt">bæd</span>, *cat* <span class="pho alt">kæt</span>, *chat* <span class="pho alt">tʃæt</span>, *dad* <span class="pho alt">dæd</span>, *dad* <span class="pho alt">dæd</span>, *drag* <span class="pho alt">dræɡ</span>, *jack* <span class="pho alt">dʒæk</span>, *fat* <span class="pho alt">fæt</span>, *gag* <span class="pho alt">ɡæɡ</span>, *has* <span class="pho alt">hæz</span>, *lab* <span class="pho alt">læb</span>, *mad* <span class="pho alt">mæd</span>, *nap* <span class="pho alt">næp</span>, *pad* <span class="pho alt">pæd</span>, *rat* <span class="pho alt">ræt</span>, *shall* <span class="pho alt">ʃæl</span>, *task* <span class="pho alt">tæsk</span>, *thank* <span class="pho alt">θæŋk</span>, *that* <span class="pho alt">ðæt</span>, *trash* <span class="pho alt">træʃ</span>, *vast* <span class="pho alt">væst</span>, *wag* <span class="pho alt">wæɡ</span>, *zag* <span class="pho alt">zæɡ</span>
\ No newline at end of file
diff --git a/1000-hours/sounds-of-american-english-old/note-syllables.md b/1000-hours/sounds-of-american-english-old/note-syllables.md
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-# 1.3 音节（Syllables）
-
-**英文的词汇由至少一个音节构成**。英文中出现频率最高的几个词，*a/an*, *the*, *of*, *to*, *for*... 等等都是单音节词汇。有的词汇可能很长，由很多音节构成。在英文词典中能找到的最长词汇总计由 19 个音节，45 个字母构成：
-
-**In English, every word is made up of at least one syllable.** The several most commonly used words in the language such as *a/an*, *the*, *of*, *to*, *for*, and others are all monosyllabic. Some words might be quite lengthy containing many syllables. In fact, if you were to flip through an English dictionary, the longest loggerhead you'd find consists whoppingly of 19 syllables with a grand total of forty-five letters:
-
-> *[Pneumonoultramicroscopicsilicovolcanoconiosis](https://en.wikipedia.org/wiki/Pneumonoultramicroscopicsilicovolcanoconiosis)* <span class="speak-word-inline" data-audio-us="/audios/En-us-pneumonoultramicroscopicsilicovolcanoconiosis.ogg.mp3"></span>
->
-> <span class="pho alt">ˌnumənəʊˌəltrəˌmaɪkrəˌskɑpɪkˌsɪləkəʊvɑlˌkeɪnəʊˌkəʊniˈəʊsəs</span>
-
-英文的音节构成大抵上有以下几种形式（其中，<span class="pho">c</span> 代表辅音，<span class="pho">v</span> 代表元音）：
-
-In general, there are the following few forms of syllable composition in English (where <span class="pho">c</span> stands for consonant and <span class="pho">v</span> means vowel):
-
-* <span class="pho">v</span>： *awe* <span class="pho alt">ɔː</span><span class="speak-word-inline" data-audio-us="/audios/awe-us.mp3"></span>
-* <span class="pho">vc</span>： *add* <span class="pho alt">æd</span><span class="speak-word-inline" data-audio-us="/audios/add-us.mp3"></span>
-* <span class="pho">cv</span>： *the* <span class="pho alt">ðə</span><span class="speak-word-inline" data-audio-us="/audios/the-us.mp3"></span>
-* <span class="pho">cvc</span>： *dog* <span class="pho alt">dɔg</span><span class="speak-word-inline" data-audio-us="/audios/dog-us.mp3"></span>
-* <span class="pho">ccv</span>： *flee* <span class="pho alt">fliː</span><span class="speak-word-inline" data-audio-us="/audios/flee-us.mp3"></span>
-* <span class="pho">vcc</span>： *east* <span class="pho alt">iːst</span><span class="speak-word-inline" data-audio-us="/audios/east-us.mp3"></span>
-* <span class="pho">cvcc</span>： *task* <span class="pho alt">tæsk</span><span class="speak-word-inline" data-audio-us="/audios/task-us.mp3"></span>
-* <span class="pho">ccvc</span>： *speed* <span class="pho alt">spiːd</span><span class="speak-word-inline" data-audio-us="/audios/speed-us.mp3"></span>
-* <span class="pho">ccvcc</span>： *thrust* <span class="pho alt">θrʌst</span><span class="speak-word-inline" data-audio-us="/audios/thrust-us.mp3"></span>
-* <span class="pho">cvccc</span>： *text* <span class="pho alt">tekst</span><span class="speak-word-inline" data-audio-us="/audios/text-us.mp3"></span>
-* <span class="pho">ccvccc</span>： *flexed* <span class="pho alt">flekst</span><span class="speak-word-inline" data-audio-us="/audios/flexed-us.mp3"></span>
-
-如果一个单词由多个音节构成的话，那么为了能够读得顺畅、清晰且易于识别，那么其中可能会有某个音节是**重音**；如果音节数量更多，可能还会有某个或某些音节是**次重音**。一般来说，**一个词汇只有一个重音**，**但有可能存在多个次重音**。比如 *serendipity* <span class="pho alt">ˌserənˈdɪpɪti</span><span class="speak-word-inline" data-audio-uk="/audios/us/serendipity-us-jen.mp3"></span>。之前的那个 *19* 个音节构成的词汇，其中有 *7* 个**次重音**，*1* 个**重音**。
-
-When a word is composed of multiple syllables, for smooth and clear pronunciation that's easily recognizable, one syllable may be stressed -- these are called *primary stresses*. If the word has many syllables, it could also have some *secondary stress*. Normally, **a single primary stress exists in each word**, **but there might be several secondary ones** - take the word *serendipity* <span class="pho alt">ˌserənˈdɪpɪti</span><span class="speak-word-inline" data-audio-uk="/audios/us/serendipity-us-jen.mp3"></span>as an example. That whopping 19-syllable-long leviathan we examined before had 7 instances of secondary stressing to accompany its lone instance of primary stressing.
-
-
-
-
-
-
-
-
-creature
-
-various
-
-reality
-
-coexist
-
-evaluate
-
-poetic
-
-diode
-
-Sequoia
-
-Video
-
-Vienna
-
-Continuation
-
-Aerobics
\ No newline at end of file
diff --git a/1000-hours/sounds-of-american-english/3.1.1-ə.md b/1000-hours/sounds-of-american-english/3.1.1-ə.md
index cab2b486..14490fcd 100644
--- a/1000-hours/sounds-of-american-english/3.1.1-ə.md
+++ b/1000-hours/sounds-of-american-english/3.1.1-ə.md
@@ -70,7 +70,7 @@
 
 另外，辅音 <span class="pho">ʃ/ʒ</span>、<span class="pho">tʃ/dʒ</span> 在发音的时候，舌尾也是同样的位置。
 
-## 3.1.1.4. 拼写
+## 3.1.1.4. 常见拼写
 
 ### <span class="pho">ə</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.1.2-ɑ.md b/1000-hours/sounds-of-american-english/3.1.2-ɑ.md
index 54ea7898..03a85f7e 100644
--- a/1000-hours/sounds-of-american-english/3.1.2-ɑ.md
+++ b/1000-hours/sounds-of-american-english/3.1.2-ɑ.md
@@ -62,7 +62,7 @@
 
 除了《剑桥英语发声词典》里的 <span class="pho">ɑː</span> 还对应着英式英语中的短元音 <span class="pho">ɒ</span> 之外，另外一个值得注意的是，英音中的 <span class="pho">ɑː</span> 在美式英语中读作 <span class="pho">æ</span>，最常见的例子是 *ask*，英音是 <span class="pho alt">ɑːsk</span><span class="speak-word-inline" data-audio-uk-male="/audios/ask-uk-male.mp3" data-audio-uk-female="/audios/ask-uk-female.mp3"></span>，美音是 <span class="pho alt">æsk</span><span class="speak-word-inline" data-audio-us-male="/audios/ask-us-male.mp3" data-audio-us-female="/audios/ask-us-female.mp3"></span>。
 
-## 3.1.1.6. 拼写（Spellings）
+## 3.1.1.6. 常见拼写
 
 ### <span class="pho">ʌ</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.1.3-i.md b/1000-hours/sounds-of-american-english/3.1.3-i.md
index 607bb352..dcd4e271 100644
--- a/1000-hours/sounds-of-american-english/3.1.3-i.md
+++ b/1000-hours/sounds-of-american-english/3.1.3-i.md
@@ -79,7 +79,7 @@
 
 <span class="pho">ɪ</span> 的儿化音 <span class="pho">ɪr</span>，其实相当于英音中的 <span class="pho">ɪə</span>，相当于是一个儿化的双元音 —— 可以理解为 <span class="pho">ɪᵊr</span> 或者 <span class="pho">ɪɚ</span>，比如，*ear* <span class="pho alt">ɪr</span> <span class="speak-word-inline" data-audio-us-male="/audios/ear-us-male.mp3" data-audio-us-female="/audios/ear-us-female.mp3"></span>…… 不过要小心，不是所有的末尾的 <span class="pho">ə</span> 都是儿化的，比如 *idea* <span class="pho alt">aɪˈdiː.ə</span> <span class="speak-word-inline" data-audio-us-male="/audios/idea-us-male.mp3" data-audio-us-female="/audios/idea-us-female.mp3"></span> 末尾的 <span class="pho">ə</span> 就没有儿化。 
 
-## 3.1.3.6. 拼写（Spellings）
+## 3.1.3.6. 常见拼写
 
 ### <span class="pho">ɪ</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.1.4-u.md b/1000-hours/sounds-of-american-english/3.1.4-u.md
index 28f9825b..039bc237 100644
--- a/1000-hours/sounds-of-american-english/3.1.4-u.md
+++ b/1000-hours/sounds-of-american-english/3.1.4-u.md
@@ -65,7 +65,7 @@
 
 美音的儿化音 <span class="pho">ʊr</span> 对应着英音的 <span class="pho">ʊə</span>，比如 *poor* <span class="pho alt">pʊr</span> <span class="speak-word-inline" data-audio-us-male="/audios/poor-us-male.mp3" data-audio-us-female="/audios/poor-us-female.mp3"></span> —— 不过请注意，这个词的英音可不是 <span class="pho alt">pʊə</span>，而是 <span class="pho alt">pɔː(r)</span><span class="speak-word-inline" data-audio-uk-male="/audios/poor-uk-male.mp3" data-audio-uk-female="/audios/poor-uk-female.mp3"></span>。
 
-## 3.1.4.5. 拼写（Spellings）
+## 3.1.4.5. 常见拼写
 
 ### <span class="pho">ʊ</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.1.5-e.md b/1000-hours/sounds-of-american-english/3.1.5-e.md
index b31723d2..b7e75629 100644
--- a/1000-hours/sounds-of-american-english/3.1.5-e.md
+++ b/1000-hours/sounds-of-american-english/3.1.5-e.md
@@ -63,7 +63,7 @@
 美音中 <span class="pho">e</span> 的儿化音 <span class="pho">er</span><span class="speak-word-inline" data-audio-us-female="/audios/air-us-female.mp3" data-audio-us-male="/audios/air-us-male.mp3"></span>，相当于英音中的双元音 <span class="pho">eə</span><span class="speak-word-inline" data-audio-uk-female="/audios/air-uk-female.mp3" data-audio-uk-male="/audios/air-uk-male.mp3"></span>，可以理解为 <span class="pho">eᵊr</span> 或者 <span class="pho">eɚ</span>…… 说的时候，请仔细体会 <span class="pho">r</span> 之前的加音 <span class="pho">ᵊ</span>。
 
 
-## 3.1.5.5. 拼写（Spellings）
+## 3.1.5.5. 常见拼写
 
 ### <span class="pho">e</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.1.6-ɔ.md b/1000-hours/sounds-of-american-english/3.1.6-ɔ.md
index cf64c009..1afd9eee 100644
--- a/1000-hours/sounds-of-american-english/3.1.6-ɔ.md
+++ b/1000-hours/sounds-of-american-english/3.1.6-ɔ.md
@@ -66,7 +66,7 @@
 另外，<span class="pho">ɔːl</span> 的组合也很常见，比如，palsy <span class="pho alt">ˈpɔːl.zi</span> <span class="speak-word-inline" data-audio-us-male="/audios/palsy-us-male.mp3" data-audio-us-female="/audios/palsy-us-female.mp3"></span> 或者 *wall* <span class="pho alt">wɑːl</span> <span class="speak-word-inline" data-audio-us-male="/audios/wall-us-male.mp3" data-audio-us-female="/audios/wall-us-female.mp3"></span>。
 
 
-## 3.1.5.5. 拼写（Spellings）
+## 3.1.5.5. 常见拼写
 
 ### <span class="pho">ɑː</span> (equivalent to British <span class="pho">ɒ</span>)
 
diff --git a/1000-hours/sounds-of-american-english/3.1.7-aɪ.md b/1000-hours/sounds-of-american-english/3.1.7-aɪ.md
index 275205e7..85a62a5f 100644
--- a/1000-hours/sounds-of-american-english/3.1.7-aɪ.md
+++ b/1000-hours/sounds-of-american-english/3.1.7-aɪ.md
@@ -83,7 +83,7 @@
 
 除了双元音之外，还有另外两个**三元音**：<span class="pho">aɪr</span><span class="speak-word-inline" data-audio-us-male="/audios/us_phonetics_sound_fire_2023feb.mp3"></span> 和 <span class="pho">aʊr</span><span class="speak-word-inline" data-audio-us-male="/audios/us_phonetics_sound_hour_2023feb.mp3"></span> —— 同样要刻意拉长。
 
-## 3.1.7.3. 拼写（Spellings）
+## 3.1.7.3. 常见拼写
 
 ### <span class="pho">aɪ</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.2.1-pb.md b/1000-hours/sounds-of-american-english/3.2.1-pb.md
index 4c1b792f..bec519d9 100644
--- a/1000-hours/sounds-of-american-english/3.2.1-pb.md
+++ b/1000-hours/sounds-of-american-english/3.2.1-pb.md
@@ -59,7 +59,7 @@
 > * <span class="pho">θ̚</span>，舌尖顶到位置 ①，而后并没有离开，所以没有气流输出，也没有随后极其轻微的 <span class="pho">ɤ</span>。比如 *math* <span class="pho alt">mæθ</span><span class="speak-word-inline" data-audio-us-male="/audios/math-stop-us-male.mp3" data-audio-us-female="/audios/math-stop-us-female.mp3"></span>
 
 
-## 3.1.2.4. 拼写（Spellings）
+## 3.1.2.4. 常见拼写
 
 ### <span class="pho">p</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.2.10-tsdz.md b/1000-hours/sounds-of-american-english/3.2.10-tsdz.md
index 4826fba9..9a870f49 100644
--- a/1000-hours/sounds-of-american-english/3.2.10-tsdz.md
+++ b/1000-hours/sounds-of-american-english/3.2.10-tsdz.md
@@ -49,7 +49,7 @@
 
 <span class="pho">ts</span> 和 <span class="pho">s</span> 从音质上来看就很不一样，但，<span class="pho">dz</span> 和 <span class="pho">z</span>，即便是母语使用者，也很难听出区别 —— 他们只是习惯了用不同的舌尖起始位置发声而已。
 
-## 3.2.10.3. 拼写（Spellings）
+## 3.2.10.3. 常见拼写
 
 ### <span class="pho">ts</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.2.11-mnŋ.md b/1000-hours/sounds-of-american-english/3.2.11-mnŋ.md
index 8b4ff3b9..2d65218c 100644
--- a/1000-hours/sounds-of-american-english/3.2.11-mnŋ.md
+++ b/1000-hours/sounds-of-american-english/3.2.11-mnŋ.md
@@ -54,7 +54,7 @@
 
 当 <span class="pho">æ</span> 在 <span class="pho">m</span> 之前的时候，部分母语使用者会添一个 <span class="pho">ᵊ</span> 进去，比如，Sam <span class="pho alt">sæm</span><span class="speak-word-inline" data-audio-us-male="/audios/sam-us-male.mp3" data-audio-us-female="/audios/sam-us-female.mp3"></span>，会被他们读成 <span class="pho alt">sæᵊm</span> —— 也有一定道理，因为 <span class="pho">m</span> 的确是音节辅音 —— 例如，*chasm* <span class="pho alt">ˈkæzm̩</span><span class="speak-word-inline" data-audio-us-male="/audios/chasm-us-male.mp3" data-audio-us-female="/audios/chasm-us-female.mp3"></span>，相当于 <span class="pho alt">ˈkæzᵊm</span>, *prism* <span class="pho alt">ˈprɪzm̩</span><span class="speak-word-inline" data-audio-us-male="/audios/prism-us-male.mp3" data-audio-us-female="/audios/prism-us-female.mp3"></span>，相当于 <span class="pho alt">ˈprɪzᵊm</span>。
 
-## 拼写（Spellings）
+## 3.2.11.4. 常见拼写
 
 ### <span class="pho">m</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.2.12-lr.md b/1000-hours/sounds-of-american-english/3.2.12-lr.md
index d7c19fc3..e29cdbaa 100644
--- a/1000-hours/sounds-of-american-english/3.2.12-lr.md
+++ b/1000-hours/sounds-of-american-english/3.2.12-lr.md
@@ -112,7 +112,7 @@
 |            ④            | <span class="pho">r</span>                                                                                                                                                                                                                                     |
 
 
-## 3.2.12.5. 拼写（Spellings）
+## 3.2.12.5. 常见拼写
 
 ### <span class="pho">l</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.2.13-wj.md b/1000-hours/sounds-of-american-english/3.2.13-wj.md
index e6650dc2..9aaede0d 100644
--- a/1000-hours/sounds-of-american-english/3.2.13-wj.md
+++ b/1000-hours/sounds-of-american-english/3.2.13-wj.md
@@ -42,7 +42,7 @@
 
 <span class="pho">w</span> 可以和另外的辅音结合作为音节开头：<span class="pho">sw</span>、<span class="pho">tw</span>、<span class="pho">dw</span>、<span class="pho">kw</span>、<span class="pho">skw</span>、<span class="pho">gw</span>…… 这其中最容易出错也最常的是 <span class="pho">kw</span>，尤其是 <span class="pho">kwɒ</span> 和 <span class="pho">kwɔː</span>，比如，*quart* <span class="pho alt">kwɔːrt</span><span class="speak-word-inline" data-audio-us-male="/audios/quart-us-male.mp3" data-audio-us-female="/audios/quart-us-female.mp3"></span>，常常会被误读为 <span class="pho alt">kɔːrt</span>（听起来和 *court* <span class="pho alt">kɔːrt</span><span class="speak-word-inline" data-audio-us-male="/audios/court-us-male.mp3" data-audio-us-female="/audios/court-us-female.mp3"></span> 同音）；再比如，*quality* <span class="pho alt">ˈkwɑː.lə.t̬i</span><span class="speak-word-inline" data-audio-us-male="/audios/quality-us-male.mp3" data-audio-us-female="/audios/quality-us-female.mp3"></span> 常常会被误读为 <span class="pho alt">ˈkɔːlɪti</span> —— 关键在于，<span class="pho">k</span> 的音之后有一个发出 <span class="pho">ʊ</span> 的嘴唇动作，否则 <span class="pho">kw</span> 就变成了 <span class="pho">k</span> —— 这个差异在母语使用者听起来异常地明显。
 
-## 3.2.13.4. 拼写（Spellings）
+## 3.2.13.4. 常见拼写
 
 ### <span class="pho">w</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.2.14-h.md b/1000-hours/sounds-of-american-english/3.2.14-h.md
index c465dc42..805609c5 100644
--- a/1000-hours/sounds-of-american-english/3.2.14-h.md
+++ b/1000-hours/sounds-of-american-english/3.2.14-h.md
@@ -37,7 +37,7 @@
 > * His house is over there. <span class="speak-word-inline" data-audio-us-male="/audios/sentence-house-is-alloy.mp3" data-audio-us-female="/audios/sentence-house-is-nova.mp3"></span>
 > * He's holding the door. <span class="speak-word-inline" data-audio-us-male="/audios/sentence-holding-the-alloy.mp3" data-audio-us-female="/audios/sentence-holding-the-nova.mp3"></span>
 
-## 拼写（Spellings）
+## 3.2.14.3. 常见拼写
 
 ### <span class="pho">h</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.2.2-td.md b/1000-hours/sounds-of-american-english/3.2.2-td.md
index bbdb5eb2..e720a64f 100644
--- a/1000-hours/sounds-of-american-english/3.2.2-td.md
+++ b/1000-hours/sounds-of-american-english/3.2.2-td.md
@@ -95,7 +95,7 @@
 
 <span class="pho">t</span> 有可能**浊化**…… 与之相对地，<span class="pho">d</span> 也可能**清化**。*ed* 在清辅音 <span class="pho">p</span>, <span class="pho">k</span>, <span class="pho">f</span>, <span class="pho">s</span>, <span class="pho">sh</span>, <span class="pho">ch</span>, <span class="pho">th</span> 之后的时候，读作 <span class="pho">t</span>，其他的时候读作 <span class="pho">d</span>。比如，*hoped* <span class="pho alt">hoʊpt</span> <span class="speak-word-inline" data-audio-us-male="/audios/hoped-us-male.mp3" data-audio-us-female="/audios/hoped-us-female.mp3"></span>，*laughed* <span class="pho alt">læft</span> <span class="speak-word-inline" data-audio-us-male="/audios/laughed-us-male.mp3" data-audio-us-female="/audios/laughed-us-female.mp3"></span>，*liked* <span class="pho alt">laɪkt</span> <span class="speak-word-inline" data-audio-us-male="/audios/liked-us-male.mp3" data-audio-us-female="/audios/liked-us-female.mp3"></span>，*watched* <span class="pho alt">wɑːtʃt</span> <span class="speak-word-inline" data-audio-us-male="/audios/watched-us-male.mp3" data-audio-us-female="/audios/watched-us-female.mp3"></span>。
 
-## 拼写（Spellings）
+## 3.2.2.5. 常见拼写
 
 ### <span class="pho">t</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.2.3-kg.md b/1000-hours/sounds-of-american-english/3.2.3-kg.md
index 311c6768..d8b8da74 100644
--- a/1000-hours/sounds-of-american-english/3.2.3-kg.md
+++ b/1000-hours/sounds-of-american-english/3.2.3-kg.md
@@ -46,7 +46,7 @@
 另外，夹在两个元音之间的 <span class="pho">k</span> 也会出现像 <span class="pho">t</span> 夹在两个元音之间时那样的浊化现象，听起来更接近 <span class="pho">g</span>。比如，*look out*<span class="speak-word-inline" data-audio-us-male="/audios/look-out-us-male.mp3" data-audio-us-female="/audios/look-out-us-female.mp3"></span>，*seek out*<span class="speak-word-inline" data-audio-us-male="/audios/seek-out-us-male.mp3" data-audio-us-female="/audios/seek-out-us-female.mp3"></span>，*woke up*<span class="speak-word-inline" data-audio-us-male="/audios/woke-up-us-male.mp3" data-audio-us-female="/audios/woke-up-us-female.mp3"></span>。
 
 
-## 拼写（Spellings）
+## 3.2.4. 常见拼写
 
 ### <span class="pho">k</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.2.4-fv.md b/1000-hours/sounds-of-american-english/3.2.4-fv.md
index 5dd9aca3..b28151cd 100644
--- a/1000-hours/sounds-of-american-english/3.2.4-fv.md
+++ b/1000-hours/sounds-of-american-english/3.2.4-fv.md
@@ -43,7 +43,7 @@
 
 另外需要注意的是，与 <span class="pho">p/b</span>、<span class="pho">t/d</span>、<span class="pho">k/g</span> 不一样，<span class="pho">f/v</span> 在发声的时候**不带**任何轻微的元音音色，哪怕是那个若有若无的 <span class="pho">ɤ</span>。
 
-## 拼写（Spellings）
+## 3.2.4.4. 常见拼写
 
 ### <span class="pho">f</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.2.5-sz.md b/1000-hours/sounds-of-american-english/3.2.5-sz.md
index 6be2342e..1941e397 100644
--- a/1000-hours/sounds-of-american-english/3.2.5-sz.md
+++ b/1000-hours/sounds-of-american-english/3.2.5-sz.md
@@ -95,7 +95,7 @@
   * *garages* <span class="pho alt">ɡəˈrɑːʒɪz</span><span class="speak-word-inline" data-audio-us-male="/audios/garages-us-male.mp3" data-audio-us-female="/audios/garages-us-female.mp3"></span>
   * *cages* <span class="pho alt">keɪdʒɪz</span><span class="speak-word-inline" data-audio-us-male="/audios/cages-us-male.mp3" data-audio-us-female="/audios/cages-us-female.mp3"></span>
 
-## 3.2.5.6. 拼写（Spellings）
+## 3.2.5.6. 常见拼写
 
 ### <span class="pho">s</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.2.6-θð.md b/1000-hours/sounds-of-american-english/3.2.6-θð.md
index 040a4bcc..01a80185 100644
--- a/1000-hours/sounds-of-american-english/3.2.6-θð.md
+++ b/1000-hours/sounds-of-american-english/3.2.6-θð.md
@@ -51,7 +51,7 @@
 > * 先发 <span class="pho">s</span> 的音，而后，把舌尖往前推一点点就接触到了牙齿，然后以与 <span class="pho">s</span> 同样的方式发音，就能听到 <span class="pho">θ</span>；然后分别说两个词 *sink* <span class="pho alt">sɪŋk</span><span class="speak-word-inline" data-audio-us-male="/audios/sink-us-male.mp3" data-audio-us-female="/audios/sink-us-female.mp3"></span> 和 *think* <span class="pho alt">θɪŋk</span><span class="speak-word-inline" data-audio-us-male="/audios/think-us-male.mp3" data-audio-us-female="/audios/think-us-female.mp3"></span>……
 > * 先发 <span class="pho">z</span> 的音，而后，把舌尖往前推一点点就接触到了牙齿，然后以与 <span class="pho">z</span> 同样的方式发音，就能听到 <span class="pho">ð</span>；然后分别说两个词 *zed* <span class="pho alt">zed</span><span class="speak-word-inline" data-audio-us-male="/audios/zed-us-male.mp3" data-audio-us-female="/audios/zed-us-female.mp3"></span> 和 *that* <span class="pho alt">ðæt</span><span class="speak-word-inline" data-audio-us-male="/audios/that-us-male.mp3" data-audio-us-female="/audios/that-us-female.mp3"></span>……
 
-## 拼写（Spellings）
+## 3.2.6.3. 常见拼写
 
 ### <span class="pho">θ</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.2.7-ʃʒ.md b/1000-hours/sounds-of-american-english/3.2.7-ʃʒ.md
index d8c9fcf1..50692c80 100644
--- a/1000-hours/sounds-of-american-english/3.2.7-ʃʒ.md
+++ b/1000-hours/sounds-of-american-english/3.2.7-ʃʒ.md
@@ -52,7 +52,7 @@
 
 少数人知道  <span class="pho">dʒ</span> 替代 <span class="pho">ʒ</span> 不是一回事，但，由于舌尖起始位置并不准确，所以他们说出来的 <span class="pho">ʒ</span> 听起来更接近 <span class="pho">r</span> —— 舌尖缩得过头了 —— <span class="pho">r</span> ④ 发声时舌尖起始位置相对于 <span class="pho">ʒ</span> ③ 要更靠后一点。
 
-## 3.2.7.3. 拼写（Spellings）
+## 3.2.7.3. 常见拼写
 
 ### <span class="pho">ʃ</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.2.8-tʃdʒ.md b/1000-hours/sounds-of-american-english/3.2.8-tʃdʒ.md
index 5b7ee54f..fcf5d279 100644
--- a/1000-hours/sounds-of-american-english/3.2.8-tʃdʒ.md
+++ b/1000-hours/sounds-of-american-english/3.2.8-tʃdʒ.md
@@ -49,7 +49,7 @@
 > * <span class="pho">ʃ... ʒ... ʃ... ʒ... ʃ... ʒ... ʃ... ʒ... ʃ... ʒ...</span>
 > * <span class="pho">tʃ... dʒ... tʃ... dʒ... tʃ... dʒ... tʃ... dʒ... tʃ... dʒ...</span>
 
-## 3.2.8.3. 拼写（Spellings）
+## 3.2.8.3. 常见拼写
 
 ### <span class="pho">ʧ</span>
 
diff --git a/1000-hours/sounds-of-american-english/3.2.9-trdr.md b/1000-hours/sounds-of-american-english/3.2.9-trdr.md
index 521a943b..a8506f21 100644
--- a/1000-hours/sounds-of-american-english/3.2.9-trdr.md
+++ b/1000-hours/sounds-of-american-english/3.2.9-trdr.md
@@ -46,7 +46,7 @@
 
 很多地区的人基于自身母语的习惯，会把 <span class="pho">tr</span> 和 <span class="pho">dr</span> 分开着连续读出的。比如，*tree*，印度人可能会把它读成 <span class="pho alt">tɤ.riː</span><span class="speak-word-inline" data-audio-other="/audios/tree-ru-ru.mp3"></span>，其中的 <span class="pho">t</span> 干脆读成 <span class="pho">d</span>，并且 <span class="pho">r</span> 还会用齿龈颤音；再比如，*driver*，可能会被俄罗斯人读成 <span class="pho alt">dɤ.raɪvə</span><span class="speak-word-inline" data-audio-other="/audios/driver-ru-ru.mp3"></span>，其中的 <span class="pho">r</span> 同样会用齿龈颤音。
 
-## 3.2.9.3. 拼写（Spellings）
+## 3.2.9.3. 常见拼写
 
 ### <span class="pho">tr</span>
 
diff --git a/1000-hours/sounds-of-american-english/4.2-words.md b/1000-hours/sounds-of-american-english/4.2-words.md
index c73e621a..0b63f24d 100644
--- a/1000-hours/sounds-of-american-english/4.2-words.md
+++ b/1000-hours/sounds-of-american-english/4.2-words.md
@@ -154,33 +154,6 @@
 
 我们其实已经用了一些英文词典里的音标中并不存在的符号才能把一些细节讲清楚，比如，阻塞音符号 <span class="pho">◌̚</span>，比如，比央元音更弱的一个音， <span class="pho">ɤ</span>，再比如喉塞音 <span class="pho">ʔ</span>…… 可即便如此，英文有那么多的单词（几十万个），有至少 7,000 个左右构成独特的音节，于是，无论如何都不大可能用一个并不完美的音标系统完美地标注任何自然语音。
 
-## 4.2.4. 背单词的方法
-
-在第三章《音素详解》中，在每个小节，针对每个音素都罗列出了 “常见拼写” —— 这才是未来扩充词汇的时候，最有效的辅助记忆手段和工具。
-
-英文的词汇构成，主要分为 “表音” 和 “表意” 两种。
-
-```mermaid
-flowchart LR
-spellings(拼写) <-.->|拆分| syllables(音节) <-.->|组合| sounds(发音)
-spellings <--> sounds
-spellings(拼写) <-.->|拆分| parts(含义) <-.->|组合| sounds(发音)
-```
-
-*apple* <span class="pho alt">ˈæp.əl</span><span class="speak-word-inline" data-audio-us-male="/audios/apple-us-male.mp3" data-audio-us-female="/audios/apple-us-female.mp3"></span> 就是一个表音构成的词汇，这是两个音节的词汇，app 对应着第一个音节 <span class="pho alt">ˈæp</span>，le 对应着第二个音节 <span class="pho alt">əl</span>。所以，记忆它的时候，不是一个字母一个字母地背，说，“*a、p、p、l、e…… apple!*”。而是，<span class="pho alt">æ</span> 对应着 a；app，<span class="pho alt">p</span> 的拼写是两个叠加的 *pp*，而后是 *le* 读作 <span class="pho alt">əl</span> —— 这样的拼写很常见，比如，*double*, *impossible*……
-
-而 *impossible* <span class="pho alt">ɪmˈpɑː.sə.bəl</span><span class="speak-word-inline" data-audio-us-male="/audios/impossible-us-male.mp3" data-audio-us-female="/audios/impossible-us-female.mp3"></span> 这个词里，就有表意的构成，*im*- 是个常见词头（prefix），和 *un*- *ir*- 一样，表示否定的含义，*possible* 是 “可能的”，*impossible* 就是 “不可能的”。进而，*possible* <span class="pho alt">ˈpɑː.sə.bəl</span><span class="speak-word-inline" data-audio-us-male="/audios/possible-us-male.mp3" data-audio-us-female="/audios/possible-us-female.mp3"></span> 就可以把它完全当作只有表音构成的词汇，*po* 读作 <span class="pho alt">ˈpɑː</span>，或者反过来，<span class="pho alt">ˈpɑː</span> 写作 *po*，*ssi* ⭤ <span class="pho alt">sə</span>，*ble* ⭤ <span class="pho alt">bəl</span>…… 反正不应该是 “*p、o、s、s、i、b、l、e…… possible!*”…… 生硬地按顺序记住 7 个字母，显然不如 “只记三个音节” 来的容易 —— 这其中，需要多注意一下的，不过是 ss（double s）而已。
-
-词根词缀，在词汇量没达到一定程度之前，实际用处不大 —— 但，到了一定地步，比如，词汇量超过 5,000 的时候，在这样扎实的基础上，稍微研究一下词根词缀，对快速且大量地做大词汇量是很有帮助的。
-
-举个例子，*ichthyosaur* <span class="pho alt">ˈɪk.θiə.sɔːr</span><span class="speak-word-inline" data-audio-us-male="/audios/ichthyosaur-us-male.mp3" data-audio-us-female="/audios/ichthyosaur-us-female.mp3"></span>，这个一看就知道并非常用的词汇，其实很简单，先从表音构成去看，<span class="pho alt">ˈɪk.θi.ə.sɔːr</span> —— 剑桥词典把它划分成了 4 个音节…… 但感觉上，第二第三个音节可以合并，<span class="pho alt">ˈɪk.θiə.sɔːr</span>，*ich* ⭤ <span class="pho alt">ˈɪk</span>, *thyo* ⭤ <span class="pho alt">θiə</span>, *saur* ⭤ <span class="pho alt">sɔːr</span>…… 而从表意的角度去看呢？前半部 *ichthyo*- 的意思是 “与鱼有关的”…… 后半部 -*saur* 是什么意思呢？各种恐龙的 “龙” 都是 -*saur* 结尾，于是，这个词的意思是 “鱼龙”……
-
-刚开始的时候，记忆单词无论如何都是吃力的。这是一个真诚的忠告，谁不信谁吃亏，爱信不信：
-
-> 千万不要尝试用任何手段去提速……
-
-—— 因为事实上谁都不可能提速，无论什么手段都不可能提速…… 真正提速的方法只有一个，**积累**。原理上，你掌握的词汇越多，记忆新词的难度就越低…… 整个看似来是个复利曲线一样有加速度的过程，到最后，真的能做到 “看一眼就记住了” 的地步。
-
 [^1]: Sound files in this list come from [CEPD online edition](https://dictionary.cambridge.org/pronunciation/).
 [^2]: *literally* 在该软件里的音标标注为 <span class="pho alt">ˈlɪtɚːəli</span> —— 虽然和《剑桥英语发声词典》略有不同，但我们依然看得懂……
 
diff --git a/1000-hours/sounds-of-american-english/5-above-ground.md b/1000-hours/sounds-of-american-english/5-above-ground.md
index b51fc918..8c7f55f3 100644
--- a/1000-hours/sounds-of-american-english/5-above-ground.md
+++ b/1000-hours/sounds-of-american-english/5-above-ground.md
@@ -1,5 +1,111 @@
-# 3. 收官（Wrapping up）
+# 5. 基础之上
 
-最后，还有一些需要注意的地方，可能更为重要 —— 其障碍竟然往往来自主观感受，而非客观事实。
+语音是基础的基础，在此之上，路漫漫其修远。
+
+## 5.1 流利
+
+学习另外一种语言，总是要处理很多与母语**不一样**的细节。
+
+> **凡是和母语发声方式不一样的地方，都是语音塑造的重点**。
+
+在语音中，最重要且最普遍被忽视的**差异**是：
+
+> 英文的**音节**在**绝大多数情况下**读出来都比亚洲语言的**字**要**长**许多……
+
+首先，英文的元音有长短之分，除了 *6* 个基础元音 <span class="pho">ʌ</span>、<span class="pho">e</span>、<span class="pho">ə</span>、<span class="pho">ɪ</span>、<span class="pho">ʊ</span>、<span class="pho">ɒ</span> 是短元音之外，剩下的十几个都是**相对更长**的元音；而亚洲语言的元音都是等长的。
+
+除此之外，在英文中，当一个短元音处于重音音节的时候，会出现因强调而发生的短元音变长的情况。比如，你可以试着说一下 *This is a **big** **city**!* —— 为了强调 *big*，你会不由自主地将它读成长长的 <span class="pho alt">biːg</span>，而不是 <span class="pho alt">bɪg</span>，如果强调 *city*，它的第一个 <span class="pho alt">sɪ</span> 也会稍微变长一点点（你可以把 <span class="pho">s</span> 拉长）……
+
+而英文的音节构成也相对更为复杂，元音前有可能是两个辅音。亚洲语言的**音节**（字）几乎没有两个辅音作为开头的情况，在英文中这种情况却非常普遍。亚洲语言的音节同样没有两三个辅音作为结尾并且还要发声清晰的情况，在英文中这种情况同样非常普遍。每个辅音都要发声清晰的话，就会占用一定的时长。比如，*flexed*, <span class="pho alt">flekst</span>，虽然整体上只是一个音节（<span class="pho">ccvccc</span> 的结构），可即便这个音节中的元音 <span class="pho">e</span> 是短元音，整体发声时它也比任何一个亚洲语言中的 “字”（同样是一个音节）都长。
+
+平均来看，英文的音节中**辅音数量**可能是亚洲语言的**两三倍以上** —— 这造成的结果就是，说英文的时候，舌头比说其他语言的时候相对要忙太多…… 并且，因此英文单个音节的发声时长也相对更长 —— 不是长一点点，而是长很多。
+
+音节上的长短差异会造成语音在韵律和节奏上的巨大差异。
+
+若是忽视了这一点，那么，在节奏韵律上的巨大差异会形成一个无法逾越的障碍。很多人压根就不知道这里有一个巨大的障碍，于是，从来就没有可能跨越它 —— 请问，你如何跨越一个你不知其存在的障碍呢？
+
+还有另外一个比较隐蔽的却也同样重要的差异：
+
+> 英语的自然语音中有大量的**塞音**存在于音节之间。这些音我们虽然听不到，也看不到发声器官的动作，但这些动作却是完整完成的 —— 也就是说，它们也是占用时长的。
+
+还没有完…… 记得吗？两个元音直接连在一起的时候，还有可能存在**加音**（<span class="pho">ʲ/ʷ</span>），以及很常见的 <span class="pho">l</span> 之前的加音 <span class="pho">ᵊ</span>……
+
+所有这些细节加在一起，造成了一个格外普遍的现象：
+
+> **亚洲人讲英文的时候速度都过快……**
+
+常常把**长元音**和**双元音**，以及美式英语特有的**半长元音**读成更短的版本（尤其是 <span class="pho">æ</span>），很多**辅音**没有清楚地发音，很多实际存在的微妙**停顿**（比如**塞音**）全都忽略，甚至可能在某些辅音之后插入了原本**不存在的元音**，但是，反过来常见的**加音**却实际上缺席……
+
+整体结果就是，同样一句话，亚洲人总是能够做到更快、很快、甚至太快地讲完。可问题在于，从理解的角度来看，在英文母语使用者耳中，几乎所有的韵律和节奏全都是错的。用错误的韵律节奏，讲的速度越快，就越难以被理解。
+
+还没有完……
+
+另外一个影响初学者讲英文时语速不正常地快的原因，更微妙，来自于一种基于普遍误解的心理压力。在这一点上，全世界的人都一样，当人们听到自己听不懂的另外一种语言的时候，总是**误以为**对方**说话速度很快**。
+
+可这就是因误解而生的幻觉。之所以幻觉对方语速快，是因为自己听不懂。听母语的时候，大脑甚至可以以句子为单位处理信息，可突然之间，要退回到音节级别，又因为那声音里充满了自己并不习惯甚至没听过的音素，不习惯的韵律和节奏，当然需要更多的精力…… 听不懂，当然记不住。于是，大脑更不够用，更是误以为对方说话太快。
+
+其实，全世界的人在说话的时候，不管使用任何语言都一样，都会不由自主地**划分意群**，下意识地**选择轻重**，并且都会有意无意地**适当停顿**，不仅是在句子之间，句子之内也有。
+
+可是，突然之间，只是因为听不懂、记不住，大脑就像一台同时运行了太多软件的电脑， CPU 过热，内存溢出，恨不得当场死机。于是，不知不觉之间产生了幻觉，就是觉得对方说话快，即便对方正在以再正常不过的语速讲话。
+
+基于上面这个普遍误解的下一个误解，同样微妙，人们常常误以为**语速够快**就能构成**讲得足够流利**。其实，**流利**的构成与**语速快慢**几乎全无关系。是否流利**更多是发音是否正确，措辞是否准确，句法和用法是否符合习惯，逻辑是否顺畅，等等等等 —— 以及，很多人可能并未意识到的另外一个很重要的东西，叫做**节奏**。
+
+所以，刚开始的时候，**要刻意放慢自己的语速**。记住，流利不靠语速，起码不只靠语速。语速过快，容易出错，越快出错越多。再说，流利也不是一上来就需要追求的东西，速度更不是。
+
+好莱坞动作明星阿诺德·施瓦辛格口音很重但表达清楚且流利 —— 这是怎么回事呢？一般来说，决定一个人讲话**流利与否**的因素，从听众角度出发，如果能够按照重要性排列的话，大抵应该如下：
+
+> - **语意完整**
+> - **Complete in meaning**
+> - **上下文足够丰富**
+> - **Rich in context**
+> - **符合习惯**
+> - **Conforms to common usage**
+> - **逻辑清晰**
+> - **Clear in logic**
+> - **语法正确**
+> - **Correct in grammar**
+> - **措辞准确**
+> - **Accurate in wording**
+> - **发音**
+> - **Pronunciation**
+> >    - 节奏
+> >    - Rhythm
+> >      - 停顿
+> >      - Stop
+> >      - 轻重
+> >      - Emphasis
+> >      - 缓急
+> >      - Pace
+> >    - 韵律
+> >    - Prosody
+> >      - 高低
+> >      - Pitch
+> >      - 起伏
+> >      - Tone
+> >    - 音素
+> >    - Phonemes
+> >      - 元音
+> >      - Vowels
+> >      - 辅音
+> >      - Consonants
+
+即便是到了相对最不重要的**音素**层面，也有重要性上的先后顺序，**元音比辅音更重要**。然而，绝大多数人在整个练习过程中，在最不重要的层面上就被卡住了…… 越是重要的越没机会练习，越是重要的，越没能力去关注 —— 这才是失败的关键吧？
+
+## 5.2 情绪
+
+学习语音的唯一有效方法只有**模仿**。在模仿的时候，最难模仿的，其实并不是我们已经讲解过的各种重点…… 还有一个可能无法模仿的，和另外一个其实可以模仿的。
+
+可能无法模仿的是对方的**音质**，因为到最后，每个人的声音都不一样，声线、音域、音量都不一样…… 通常来说，除非是模仿能力特别强的人，才能做到发出和别人同样音质的声音 —— 虽然不是谁都做不到，但，这个要求多少的确有点过份……
+
+然而，的确有确实可以模仿的 —— **情绪**。紧张、兴奋、疲惫、失望、恐惧、悲伤、快乐、期待，等等等等。就算不能模仿得一模一样，终归能按照自己的方式去表现同样的情绪 —— 瞬间就能做到八九不离十。
+
+用 AI 生成的真人语音，最大的问题在于，它目前还不能做到**情绪饱满**，它只是尽量做到了 “听起来像是真人说话”，虽然已经很好，但就是缺乏情绪表达 —— 它也的确没有什么真正的情绪……
+
+各种惊悚片动作片都很精彩，很吸引人…… 可实际上它们真的不是最好的学习材料，因为这类影视内容的对话事实上非常枯燥，警匪片里最常重复的，只不过是 *Freeze! Drop your gun!* 要么就是 *You have the right to remain silent*... 战争片里最常重复的更加迷离，反反复复最多的都是 *Get down!* 或者 *Go! Go! Go!* —— 动作太多，语言就只能太少。至于情绪么，往往更多的只有愤怒或者悲伤。
+
+这就是为什么**生活情景剧**和**脱口秀**常常是很好的学习材料的重要原因 —— 主要是情绪丰富且饱满。另外，**纪录片**往往都是很好的学习材料。它们的特点是，措辞简单明了，语速慢，吐字清晰，并且情绪饱满。情绪更加饱满的，是各种给青少年甚至婴幼儿看的动画片或者绘本讲解，情绪丰富饱满到夸张的地步……
+
+如果觉得这些都太尴尬，还有个办法是不断学唱**英文歌曲** —— 每个音节都带着不同的音高曲调，甚至有可能一个词就唱了满满一两个小节，容不得一丝的错误，真的是绝佳的练习场景。
+
+语音的功用，如果说有 *20%* 是用来传递对事实的感受的话，那么，剩下的 *80%* 肯定并且只能用来传递情绪，不是吗？一直以来，大家在 “学外语” 的时候，都太理智了，不是吗？理智的确是一种很好的品质，但，有时候，它可能会成为不可逾越的障碍…… 真的很可惜！
 
-Finally, there's something more crucial to keep in mind - the obstacles we face often stem from our own subjective perceptions, rather than objective facts.
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diff --git a/1000-hours/sounds-of-american-english/5.1-fluency.md b/1000-hours/sounds-of-american-english/5.1-fluency.md
deleted file mode 100644
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-# 3.1 流利（Fluency）
-
-学习另外一种语言，总是要处理很多与母语**不一样**的细节。
-
-Learning another language always involves navigating a myriad of details that differ from native tongue.
-
-> **凡是和母语发声方式不一样的地方，都是语音塑造的重点**。
->
-> **Any differences in pronunciation from your native language should be the focus of speech training**.
-
-在语音中，最重要且最普遍被忽视的**差异**是：
-
-One of the most important and often overlooked *differences* is:
-
-> 英文的**音节**在**绝大多数情况下**读出来都比亚洲语言的**字**要**长**许多……
->
-> English syllables, in most cases, are pronounced *much longer* than the individual characters in Asian languages...
-
-首先，英文的元音有长短之分，除了 *6* 个基础元音 <span class="pho">ʌ</span>、<span class="pho">e</span>、<span class="pho">ə</span>、<span class="pho">ɪ</span>、<span class="pho">ʊ</span>、<span class="pho">ɒ</span> 是短元音之外，剩下的十几个都是**相对更长**的元音；而亚洲语言的元音都是等长的。
-
-Firstly, English vowels have variations in length. Aside from the *6* basic short vowels <span class="pho">ʌ</span>, <span class="pho">e</span>, <span class="pho">ə</span>, <span class="pho">ɪ</span>, <span class="pho">ʊ</span>, and <span class="pho">ɒ</span>, the remaining more than dozen vowels are relatively longer. In contrast, vowels in Asian languages are all of equal length.
-
-除此之外，在英文中，当一个短元音处于重音音节的时候，会出现因强调而发生的短元音变长的情况。比如，你可以试着说一下 *This is a **big** **city**!* —— 为了强调 *big*，你会不由自主地将它读成长长的 <span class="pho alt">biːg</span>，而不是 <span class="pho alt">bɪg</span>，如果强调 *city*，它的第一个 <span class="pho alt">sɪ</span> 也会稍微变长一点点（你可以把 <span class="pho">s</span> 拉长）……
-
-In English, a short vowel in a stressed syllable can *elongate* when emphasized. For example, try saying, *This is a **big** **city**!* You'll notice that to emphasize *big*, you naturally stretch it into a long-sounding <span class="pho alt">biːg</span>, instead of the short <span class="pho alt">bɪg</span>. If you stress *city*, the first <span class="pho alt">sɪ</span> will also lengthen slightly - you can stretch the <span class="pho">s</span> sound.
-
-而英文的音节构成也相对更为复杂，元音前有可能是两个辅音。亚洲语言的**音节**（字）几乎没有两个辅音作为开头的情况，在英文中这种情况却非常普遍。亚洲语言的音节同样没有两三个辅音作为结尾并且还要发声清晰的情况，在英文中这种情况同样非常普遍。每个辅音都要发声清晰的话，就会占用一定的时长。比如，*flexed*, <span class="pho alt">flekst</span>，虽然整体上只是一个音节（<span class="pho">ccvccc</span> 的结构），可即便这个音节中的元音 <span class="pho">e</span> 是短元音，整体发声时它也比任何一个亚洲语言中的 “字”（同样是一个音节）都长。
-
-English syllables can also be more complex, often with two consonants in the beginning of a vowel. This contrasts with Asian languages, where syllables (or *characters*) rarely start with two consonants. Similarly, English often ends syllables with two or three clear-sounding consonants, while this is less common in Asian languages. Each consonant requires a certain amount of time to articulate clearly. For example, the word *flexed*, pronounced <span class="pho alt">flekst</span>, although technically one syllable (<span class="pho">ccvccc</span> structure), takes longer to say than any single syllable (or *character*) in an Asian language, even though the vowel <span class="pho">e</span> in *flexed* is short.
-
-平均来看，英文的音节中**辅音数量**可能是亚洲语言的**两三倍以上** —— 这造成的结果就是，说英文的时候，舌头比说其他语言的时候相对要忙太多…… 并且，因此英文单个音节的发声时长也相对更长 —— 不是长一点点，而是长很多。
-
-On average, the number of consonants in English syllables is likely more than double that of Asian languages. This means that speaking English requires our tongues to be busier than when speaking in most other languages. Moreover, this causes each English syllable to be pronounced in a relatively longer duration - not just a bit longer, but *significantly* longer.
-
-音节上的长短差异会造成语音在韵律和节奏上的巨大差异。
-
-The difference in syllable length can lead to a significant difference in speech prosody and rhythm.
-
-若是忽视了这一点，那么，在节奏韵律上的巨大差异会形成一个无法逾越的障碍。很多人压根就不知道这里有一个巨大的障碍，于是，从来就没有可能跨越它 —— 请问，你如何跨越一个你不知其存在的障碍呢？
-
-If this is overlooked, the resulting significant difference in prosody and rhythm can become an insurmountable barrier. Many people are oblivious to this huge obstacle, hence, they never get the chance to overcome it. After all, how can you overcome a barrier you don't even know exists?
-
-还有另外一个比较隐蔽的却也同样重要的差异：
-
-There's another less noticeable yet equally crucial difference:
-
-> 英语的自然语音中有大量的**塞音**存在于音节之间。这些音我们虽然听不到，也看不到发声器官的动作，但这些动作却是完整完成的 —— 也就是说，它们也是占用时长的。
->
-> In natural English speech, there are numerous *stop* sounds interspersed between syllables. We may not hear these sounds or see the articulator in action, but the actions are fully completed, meaning they also take up time.
-
-还没有完…… 记得吗？两个元音直接连在一起的时候，还有可能存在**加音**（<span class="pho">ʲ/ʷ</span>），以及很常见的 <span class="pho">l</span> 之前的加音 <span class="pho">ᵊ</span>……
-
-And there's more... remember? When two vowels are connected, there might also be a **glide sound** (<span class="pho">ʲ/ʷ</span>), and that common schwa <span class="pho">ᵊ</span> added before <span class="pho">l</span>...
-
-所有这些细节加在一起，造成了一个格外普遍的现象：
-
-All these nuances combined result in a particularly common phenomenon:
-
-> **亚洲人讲英文的时候速度都过快……**
->
-> **Asian people often speak English too quickly...**
-
-常常把**长元音**和**双元音**，以及美式英语特有的**半长元音**读成更短的版本（尤其是 <span class="pho">æ</span>），很多**辅音**没有清楚地发音，很多实际存在的微妙**停顿**（比如**塞音**）全都忽略，甚至可能在某些辅音之后插入了原本**不存在的元音**，但是，反过来常见的**加音**却实际上缺席……
-
-Asian speakers often shorten long vowels and diphthongs, as well as the unique half-long vowels in American English, especially the <span class="pho">æ</span> sound. Many consonants aren't clearly pronounced, and subtle stops that should be there are often overlooked. Sometimes, vowels are added where they don't exist, yet, ironically, added sounds that should be present are often missing.
-
-整体结果就是，同样一句话，亚洲人总是能够做到更快、很快、甚至太快地讲完。可问题在于，从理解的角度来看，在英文母语使用者耳中，几乎所有的韵律和节奏全都是错的。用错误的韵律节奏，讲的速度越快，就越难以被理解。
-
-The result is that Asians tend to speak English much faster than native speakers. The problem, however, is that from a comprehension standpoint, the prosody and rhythm are all wrong to native English ears. The faster you speak with incorrect prosody and rhythm, the harder it becomes to understand.
-
-还没有完……
-
-The story doesn't end there...
-
-另外一个影响初学者讲英文时语速不正常地快的原因，更微妙，来自于一种基于普遍误解的心理压力。在这一点上，全世界的人都一样，当人们听到自己听不懂的另外一种语言的时候，总是**误以为**对方**说话速度很快**。
-
-Another subtle factor that often makes beginners speak English unnaturally fast originates from a psychological pressure based on a widespread misunderstanding. This is a universal experience: when people hear a language they do not understand, they often *mistakenly believe* that the speaker is *talking too fast*.
-
-可这就是因误解而生的幻觉。之所以幻觉对方语速快，是因为自己听不懂。听母语的时候，大脑甚至可以以句子为单位处理信息，可突然之间，要退回到音节级别，又因为那声音里充满了自己并不习惯甚至没听过的音素，不习惯的韵律和节奏，当然需要更多的精力…… 听不懂，当然记不住。于是，大脑更不够用，更是误以为对方说话太快。
-
-However, this perception is nothing but an illusion born out of misunderstanding. The reason we perceive foreign speakers as speaking quickly is simply because we don't understand what they're saying. When we listen to our native language, our brain can process information on the sentence level. Suddenly, when faced with a foreign language, we're thrust back to the syllable level. With unfamiliar phonemes, prosody and rhythms, we, of course, need more mental effort... If we don't understand, we certainly can't remember. As a result, our brains struggle more, enhancing this illusion of rapid speech.
-
-其实，全世界的人在说话的时候，不管使用任何语言都一样，都会不由自主地**划分意群**，下意识地**选择轻重**，并且都会有意无意地**适当停顿**，不仅是在句子之间，句子之内也有。
-
-In reality, all speakers, regardless of the language they're using, instinctively chunk phrases, choose stress levels subconsciously, and take deliberate pauses. These pauses are not only between sentences but also within them.
-
-可是，突然之间，只是因为听不懂、记不住，大脑就像一台同时运行了太多软件的电脑， CPU 过热，内存溢出，恨不得当场死机。于是，不知不觉之间产生了幻觉，就是觉得对方说话快，即便对方正在以再正常不过的语速讲话。
-
-But then, all of a sudden, just because you can't understand or remember, your brain starts working like a computer running too many apps at once. The CPU overheats, memory overflows, and it feels like it's about to crash right there and then. Without realizing it, you start to imagine that the other person is speaking too quickly, even though they're speaking at a perfectly normal pace.
-
-基于上面这个普遍误解的下一个误解，同样微妙，人们常常误以为**语速够快**就能构成**讲得足够流利**。其实，**流利**的构成与**语速快慢**几乎全无关系。是否流利**更多是发音是否正确，措辞是否准确，句法和用法是否符合习惯，逻辑是否顺畅，等等等等 —— 以及，很多人可能并未意识到的另外一个很重要的东西，叫做**节奏**。
-
-Building on the common misconception mentioned above, there's another subtle misperception often held: people tend to equate *speaking fast* with *being fluent*. In reality, *fluency* has almost nothing to do with *the speed of speech*. True fluency hinges on accurate pronunciation, precise choice of words, adherence to customary syntax and usage, smooth logical presentation, and so on. What's more, something many people may not fully realize is the crucial role *rhythm* plays in fluent speech.
-
-所以，刚开始的时候，**要刻意放慢自己的语速**。记住，流利不靠语速，起码不只靠语速。语速过快，容易出错，越快出错越多。再说，流利也不是一上来就需要追求的东西，速度更不是。
-
-So, in the beginning, it's crucial to *deliberately slow down your pace of speech*. Bear in mind, fluency doesn't depend solely on the speed of speech. Speaking too quickly can lead to mistakes, and the faster you speak, the more errors you're likely to make. Besides, fluency isn't something you need to aim for right off the bat, and speed is even less so.
-
-好莱坞动作明星阿诺德·施瓦辛格口音很重但表达清楚且流利 —— 这是怎么回事呢？一般来说，决定一个人讲话**流利与否**的因素，从听众角度出发，如果能够按照重要性排列的话，大抵应该如下：
-
-Consider Hollywood action star Arnold Schwarzenegger. His accent is heavy, but he communicates clearly and fluently - how can this be? Generally, the factors that determine whether a person's speech is *fluent or not* can be lined up in terms of importance from the audience's perspective, roughly as follows:
-
-> - **语意完整**
-> - **Complete in meaning**
-> - **上下文足够丰富**
-> - **Rich in context**
-> - **符合习惯**
-> - **Conforms to common usage**
-> - **逻辑清晰**
-> - **Clear in logic**
-> - **语法正确**
-> - **Correct in grammar**
-> - **措辞准确**
-> - **Accurate in wording**
-> - **发音**
-> - **Pronunciation**
-> >    - 节奏
-> >    - Rhythm
-> >      - 停顿
-> >      - Stop
-> >      - 轻重
-> >      - Emphasis
-> >      - 缓急
-> >      - Pace
-> >    - 韵律
-> >    - Prosody
-> >      - 高低
-> >      - Pitch
-> >      - 起伏
-> >      - Tone
-> >    - 音素
-> >    - Phonemes
-> >      - 元音
-> >      - Vowels
-> >      - 辅音
-> >      - Consonants
-
-即便是到了相对最不重要的**音素**层面，也有重要性上的先后顺序，**元音比辅音更重要**。然而，绝大多数人在整个练习过程中，在最不重要的层面上就被卡住了…… 越是重要的越没机会练习，越是重要的，越没能力去关注 —— 这才是失败的关键吧？
-
-Even at the seemingly least important level of phonemes, there's a hierarchy of importance: *vowels are more critical than consonants*. However, most people get stuck at this least significant level during their practice... The more crucial something is, the less opportunity they have to practice it, the less capacity they have to focus on it. Isn't this the real crux of failure?
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diff --git a/1000-hours/sounds-of-american-english/5.2-emotions.md b/1000-hours/sounds-of-american-english/5.2-emotions.md
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index 360cf48e..00000000
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-# 3.2 情绪（Emotions）
-
-学习语音的唯一有效方法只有模仿。在模仿的时候，最难模仿的，其实并不是我们已经讲解过的各种重点…… 还有一个可能无法模仿的，和另外一个其实可以模仿的。
-
-The only effective way to learn speech is by *imitation*. The most challenging part of this process isn't necessarily the key points we've previously discussed... There are two things that may come to mind: one that might be impossible to mimic, and another that could actually be copied.
-
-可能无法模仿的是对方的**音质**，因为到最后，每个人的声音都不一样，声线、音域、音量都不一样…… 通常来说，除非是模仿能力特别强的人，才能做到发出和别人同样音质的声音 —— 虽然不是谁都做不到，但，这个要求多少的确有点过份……
-
-The thing that might be impossible to mimic is someone else's *voice quality*. In the end, each person's voice is unique - the pitch, range, and volume all differ. Usually, only those with a particularly strong ability to imitate can perfectly replicate the voice quality of another. While not impossible, this expectation can indeed be a bit excessive.
-
-然而，的确有确实可以模仿的 —— **情绪**。紧张、兴奋、疲惫、失望、恐惧、悲伤、快乐、期待，等等等等。就算不能模仿得一模一样，终归能按照自己的方式去表现同样的情绪 —— 瞬间就能做到八九不离十。
-
-However, there is something that can certainly be mimicked - *emotions*. Be it nervousness, excitement, fatigue, disappointment, fear, sadness, joy, anticipation, and so on. Even if you can't mimic these emotions identically, you can certainly express the same feelings in your own way - and instantly get pretty close to the mark.
-
-用 AI 生成的真人语音，最大的问题在于，它目前还不能做到**情绪饱满**，它只是尽量做到了 “听起来像是真人说话”，虽然已经很好，但就是缺乏情绪表达 —— 它也的确没有什么真正的情绪……
-
-The biggest issue with AI-generated human voices is that they currently lack emotional depth. They strive to *sound like a human speaking* and while they do this well, they fall short in conveying emotion - which is understandable, as they don't genuinely feel any emotions.
-
-各种惊悚片动作片都很精彩，很吸引人…… 可实际上它们真的不是最好的学习材料，因为这类影视内容的对话事实上非常枯燥，警匪片里最常重复的，只不过是 *Freeze! Drop your gun!* 要么就是 *You have the right to remain silent*... 战争片里最常重复的更加迷离，反反复复最多的都是 *Get down!* 或者 *Go! Go! Go!* —— 动作太多，语言就只能太少。至于情绪么，往往更多的只有愤怒或者悲伤。
-
-Action movies or thrillers may be captivating, but they are not the best study materials. The dialogues in these movies can be quite dry. Police dramas seem to endlessly repeat phrases like *Freeze! Drop your gun!* or *You have the right to remain silent*. In war movies, you'll frequently hear *Get down!* or *Go! Go! Go!* The abundance of action scenes leaves little room for language. As for emotions, only expressions of anger and sadness tend to dominate.
-
-这就是为什么**生活情景剧**和**脱口秀**常常是很好的学习材料的重要原因 —— 主要是情绪丰富且饱满。另外，**纪录片**往往都是很好的学习材料。它们的特点是，措辞简单明了，语速慢，吐字清晰，并且情绪饱满。情绪更加饱满的，是各种给青少年甚至婴幼儿看的动画片或者绘本讲解，情绪丰富饱满到夸张的地步……
-
-That's why *sitcoms* and *talk shows* often make great learning resources. They are rich in emotional content. *Documentaries* can also serve as excellent study materials, which feature simple and clear wording, slow speech, clear articulation, and full emotions. Even more emotionally expressive are *shows and storybooks for teenagers and toddlers*, where emotions are exaggerated to the extreme.
-
-如果觉得这些都太尴尬，还有个办法是不断学唱**英文歌曲** —— 每个音节都带着不同的音高曲调，甚至有可能一个词就唱了满满一两个小节，容不得一丝的错误，真的是绝佳的练习场景。
-
-If you find these a bit awkward, another approach is to continuously learn English *songs*. Each syllable carries a different tone or melody, and a single word could fill a couple of bars, leaving no room for errors. It's indeed an excellent practice setting.
-
-语音的功用，如果说有 *20%* 是用来传递对事实的感受的话，那么，剩下的 *80%* 肯定并且只能用来传递情绪，不是吗？一直以来，大家在 “学外语” 的时候，都太理智了，不是吗？理智的确是一种很好的品质，但，有时候，它可能会成为不可逾越的障碍…… 真的很可惜！
-
-If we say that *20%* of voice utility is for conveying feelings towards *facts*, then the remaining *80%* must be intended to express *emotions*, right? Perhaps we've been too logical when learning foreign languages, haven't we? While rationality is a good trait, it can sometimes turn into an insurmountable hurdle... which is truly a pity!
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+# 6. 词汇构建
+
+千万不要天真地把 “背单词” 和 “学英语” 等同起来…… 构建词汇量，的确是一个重要的环节，但，它不仅不是全部，甚至不是最重要的环节。
+
+另外一个关键在于，在构建词汇量的过程中，最重要的是 “**文本与语音之间不可分割的紧密联系**” —— 不知道为什么，觉得大多数人竟然觉得这最关键的东西根本无所谓…… 但，那些人早晚会因为他们的误解付出惨重的代价。
+
+## 6.1. 背单词的最有效方法
+
+在第三章《音素详解》中，在每个小节，针对每个音素都罗列出了 “常见拼写” —— 这才是未来扩充词汇的时候，最有效的辅助记忆手段和工具。
+
+英文的词汇构成，主要分为 “表音” 和 “表意” 两种。
+
+```mermaid
+flowchart LR
+spellings(拼写) <-.->|拆分| syllables(音节构成) <-.->|组合| sounds(发音)
+spellings <--> sounds
+spellings(拼写) <-.->|拆分| parts(含义组件) <-.->|组合| sounds(发音)
+```
+
+*apple* <span class="pho alt">ˈæp.əl</span><span class="speak-word-inline" data-audio-us-male="/audios/apple-us-male.mp3" data-audio-us-female="/audios/apple-us-female.mp3"></span> 就是一个表音构成的词汇，这是两个音节的词汇，app 对应着第一个音节 <span class="pho alt">ˈæp</span>，le 对应着第二个音节 <span class="pho alt">əl</span>。所以，记忆它的时候，不是一个字母一个字母地背，说，“*a、p、p、l、e…… apple!*”。而是，<span class="pho alt">æ</span> 对应着 a；app，<span class="pho alt">p</span> 的拼写是两个叠加的 *pp*，而后是 *le* 读作 <span class="pho alt">əl</span> —— 这样的拼写很常见，比如，*double*, *impossible*……
+
+而 *impossible* <span class="pho alt">ɪmˈpɑː.sə.bəl</span><span class="speak-word-inline" data-audio-us-male="/audios/impossible-us-male.mp3" data-audio-us-female="/audios/impossible-us-female.mp3"></span> 这个词里，就有表意的构成，*im*- 是个常见词头（prefix），和 *un*- *ir*- 一样，表示否定的含义，*possible* 是 “可能的”，*impossible* 就是 “不可能的”。进而，*possible* <span class="pho alt">ˈpɑː.sə.bəl</span><span class="speak-word-inline" data-audio-us-male="/audios/possible-us-male.mp3" data-audio-us-female="/audios/possible-us-female.mp3"></span> 就可以把它完全当作只有表音构成的词汇，*po* 读作 <span class="pho alt">ˈpɑː</span>，或者反过来，<span class="pho alt">ˈpɑː</span> 写作 *po*，*ssi* ⭤ <span class="pho alt">sə</span>，*ble* ⭤ <span class="pho alt">bəl</span>…… 反正不应该是 “*p、o、s、s、i、b、l、e…… possible!*”…… 生硬地按顺序记住 7 个字母，显然不如 “只记三个音节” 来的容易 —— 这其中，需要多注意一下的，不过是 ss（double s）而已。
+
+另外，常用词汇中其实有不少是 “组合词汇”（*compound words*），各个组成部分也都是 “表意” 的。比如 *classroom* <span class="pho alt">ˈklæs.ruːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/classroom-us-male.mp3" data-audio-us-female="/audios/classroom-us-female.mp3"></span>, *doorbell* <span class="pho alt">ˈdɔːr.bel</span> <span class="speak-word-inline" data-audio-us-male="/audios/doorbell-us-male.mp3" data-audio-us-female="/audios/doorbell-us-female.mp3"></span>, *handwriting* <span class="pho alt">ˈhændˌraɪ.t̬ɪŋ</span> <span class="speak-word-inline" data-audio-us-male="/audios/handwriting-us-male.mp3" data-audio-us-female="/audios/handwriting-us-female.mp3"></span>, *sunshine* <span class="pho alt">ˈsʌn.ʃaɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/sunshine-us-male.mp3" data-audio-us-female="/audios/sunshine-us-female.mp3"></span>, *upstairs* <span class="pho alt">ʌpˈsterz</span> <span class="speak-word-inline" data-audio-us-male="/audios/upstairs-us-male.mp3" data-audio-us-female="/audios/upstairs-us-female.mp3"></span> 等等。
+
+词根词缀，尤其是那些来自于拉丁语的词根词缀，在词汇量没达到一定程度之前，实际用处不大 —— 但，到了一定地步，比如，词汇量超过 5,000 的时候，在这样扎实的基础上，稍微研究一下词根词缀，对快速且大量地做大词汇量是很有帮助的。
+
+举个例子，*ichthyosaur* <span class="pho alt">ˈɪk.θiə.sɔːr</span><span class="speak-word-inline" data-audio-us-male="/audios/ichthyosaur-us-male.mp3" data-audio-us-female="/audios/ichthyosaur-us-female.mp3"></span>，这个一看就知道并非常用的词汇，其实很简单，先从表音构成去看，<span class="pho alt">ˈɪk.θi.ə.sɔːr</span> —— 剑桥词典把它划分成了 4 个音节…… 但感觉上，第二第三个音节可以合并，<span class="pho alt">ˈɪk.θiə.sɔːr</span>，*ich* ⭤ <span class="pho alt">ˈɪk</span>, *thyo* ⭤ <span class="pho alt">θiə</span>, *saur* ⭤ <span class="pho alt">sɔːr</span>…… 而从表意的角度去看呢？前半部 *ichthyo*- 的意思是 “与鱼有关的”…… 后半部 -*saur* 是什么意思呢？各种恐龙的 “龙” 都是 -*saur* 结尾，于是，这个词的意思是 “鱼龙”……
+
+记忆词汇的最朴素最有效方法，就是把它的拼写、读音和意义联系起来 —— 这原本是文字本来的结构和意义。
+
+```mermaid
+flowchart LR
+
+sounds(读音)<--->meanings(意义)
+meanings<--->spellings(拼写)
+sounds<--->spellings
+```
+
+除此之外，其他的任何所谓的 “方法”，都不仅无效，甚至只有副作用，弊大于利。比如什么 “谐音记忆法” 或者 “趣味记忆法” 什么的，它们都违背大脑对语言文字的基本工作机制，根本不可能提高效率，只会增加不必要的负担 —— 虽然有时候觉竟然觉得有点意思……
+
+人们失败的原因很简单，他们总想 “更省事儿一点”。坐在那里只用眼睛看，既不动口也不动手，也因此实际上更少动脑。只调用一个器官和同时调用多个器官是不一样的，前者好像更省事儿，可实际上由于脑力调用太少，导致的结果是 “效果几近于零”。
+
+学外语的人十有八九失败。很多失败的人都曾经去问过老师，“老师，我背单词不记发音行不行？” “老师，我背单词不记拼写行不行？” 这种荒谬至极的问题问出来，并不是想要什么答案，只是想要一个 “偷懒认证”，给自己的偷懒找个背书…… 还别说，还真有老师说 “可以！” 因为真的有相当数量相当比例的老师，通过这种方法获得更多来自学生的好感，进而提高自己的收入……
+
+刚开始的时候，记忆单词无论如何都是吃力的。这是一个真诚的忠告，谁不信谁吃亏，爱信不信：
+
+> 千万不要尝试用任何手段去提速……
+
+—— 因为事实上谁都不可能提速，无论什么手段都不可能提速…… 真正提速的方法只有一个，**积累**。
+
+扩充词汇，是有**加速度**的过程 —— 可以越来越快…… 可是，在最初的时候，速度很低，加速度为零，所以总是感觉超级吃力。然而，词汇之间是有关联的，对大脑来说，一个生词与已有的词汇关联越多，越容易记住。也就是说，已有词汇量越多，新词可能与它们产生的关联越多，所以才越来越容易。当你的词汇量超过三五千的时候，你就会感觉很多生词几乎看一眼就记得住，无论是拼写还是读音还是其意义甚至其用法 —— 整个看似来是个**复利曲线**一样有**越来越大的加速度**的过程。
+
+倒是有个窍门。**直接背例句**…… 对大脑来说，“多朗读几遍例句” 远比 “只把力气花在某一个单词或者词组上” 来得更为轻松。在语言方面就是这样，你做得越多，对大脑来说越轻松，反过来，你做得越少，所谓 “省事儿” 逐步形成的，对大脑来说只能是不可逾越的障碍。
+
+进而，最靠谱的扩大词汇量方法：**精读**。找到自己真正感兴趣的书（小说类、非小说类各几本），遇到生词就查，逐一消灭 —— 每本书都要读若干遍（所以一定要选自己真迷恋的书）…… 读着读着，词汇量就大了，句法障碍就消失了，理解能力就提高了，阅读速度就飞快了…… 各种语言都是这样的。哪怕是我们的母语，我们对母语的掌控能力，也是这么练出来的 —— 学校里的语文课和语文老师，从来都帮不上什么忙…… 说点刻薄的话，这些语文老师啊，他们的唯一作用就是在考试里给绝大多数学生设置奇怪的障碍。
+
+## 6.2. 多音拼写
+
+之前的章节里，都罗列了对应每个音素可能的拼写。有些拼写只对应一个读音，比如，**h** 就只对应着 <span class="pho">h</span>；但，有一些拼写可能对应着多个读音。以下是一个总结整理，需要经过反复对照而谙熟于心。
+
+In the previous chapters, we listed the possible spellings for each phoneme. Some spellings correspond to just one sound, like **h**, which only corresponds to <span class="pho">h</span>. However, some spellings can correspond to multiple sounds. Here's a summary that needs to be reviewed repeatedly until it becomes second nature.
+
+## 6.2.1. 元音拼写
+
+<div class="two-column">
+
+- "**a**": `ɑː`, `æ`, `e`, `eɪ`, `ə`
+- "**ai**": `e`, `eɪ`
+- "**al**": `ɑː`, `æ`, `ɔː`
+- "**ar**": `ɑːr`, `ɚ`
+- "**au**": `ɑː`, `aʊ`, `ɔː`
+- "**e**": `e`, `ə`, `ɪ`, `iː`
+- "**ea**": `e`, `iː`, `eɪ`
+- "**ear**": `er`, `ɪr`, `ɝː`
+- "**er**": `ɚ`, `ɝː`
+- "**ew**": `uː`, `oʊ`
+- "**i**": `ɪ`, `aɪ`, `ə`, `j`,
+- "**ie**": `iː`, `e`, `aɪ`
+- "**o**": `ʌ`, `ɑː`, `ə`, `ɔː`, `uː`, `oʊ`
+- "**oo**": `ʌ`, `ʊ`, `uː`
+- "**oor**": `ʊr`, `ɔːr`
+- "**or**": `ɚ`, `ɝː`, `ɔːr`
+- "**ou**": `ʌ`, `ʊ`, `ə`, `aʊ`
+- "**ough**": `ɑː`, `oʊ`
+- "**our**": `aʊr`, `ʊr`, `ɔːr`
+- "**ow**": `aʊ`, `oʊ`
+- "**u**": `ʌ`, `ʊ`, `uː`, `ə`
+- "**ure**": `ɚ`, `ʊr`
+
+</div>
+
+## 6.2.2. 辅音拼写
+
+<div class="two-column">
+
+- "**c**": `s`, `k`
+- "**ch**": `ʃ`, `k`, `ʧ`
+- "**d**": `d`, `dʒ`
+- "**g**": `g`, `dʒ`, `ʒ`
+- "**j**": `j`, `dʒ`
+- "**s**": `s`, `z`, `ʃ`, `ʒ`
+- "**ss**": `s`, `ʃ`
+- "**th**": `ð`, `θ`, `t`
+- "**y**": `ɪ`, `aɪ`, `i`, `j`
+- "**z**": `z`, `ʒ`
+
+</div>
+
+## 6.3. 常见组合词汇
+
+<div class="two-column">
+
+1. airplane <span class="pho alt">ˈer.pleɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/airplane-us-male.mp3" data-audio-us-female="/audios/airplane-us-female.mp3"></span>
+2. airport <span class="pho alt">ˈer.pɔːrt</span> <span class="speak-word-inline" data-audio-us-male="/audios/airport-us-male.mp3" data-audio-us-female="/audios/airport-us-female.mp3"></span>
+3. backyard <span class="pho alt">ˌbækˈjɑːrd</span> <span class="speak-word-inline" data-audio-us-male="/audios/backyard-us-male.mp3" data-audio-us-female="/audios/backyard-us-female.mp3"></span>
+4. bedroom <span class="pho alt">ˈbed.ruːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/bedroom-us-male.mp3" data-audio-us-female="/audios/bedroom-us-female.mp3"></span>
+5. birthday <span class="pho alt">ˈbɝːθ.deɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/birthday-us-male.mp3" data-audio-us-female="/audios/birthday-us-female.mp3"></span>
+6. blackboard <span class="pho alt">ˈblæk.bɔːrd</span> <span class="speak-word-inline" data-audio-us-male="/audios/blackboard-us-male.mp3" data-audio-us-female="/audios/blackboard-us-female.mp3"></span>
+7. bookstore <span class="pho alt">ˈbʊk.stɔːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/bookstore-us-male.mp3" data-audio-us-female="/audios/bookstore-us-female.mp3"></span>
+8. brainstorm <span class="pho alt">ˈbreɪn.stɔːrm</span> <span class="speak-word-inline" data-audio-us-male="/audios/brainstorm-us-male.mp3" data-audio-us-female="/audios/brainstorm-us-female.mp3"></span>
+9. breakfast <span class="pho alt">ˈbrek.fəst</span> <span class="speak-word-inline" data-audio-us-male="/audios/breakfast-us-male.mp3" data-audio-us-female="/audios/breakfast-us-female.mp3"></span>
+10. classroom <span class="pho alt">ˈklæs.ruːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/classroom-us-male.mp3" data-audio-us-female="/audios/classroom-us-female.mp3"></span>
+11. cupcake <span class="pho alt">ˈkʌp.keɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/cupcake-us-male.mp3" data-audio-us-female="/audios/cupcake-us-female.mp3"></span>
+12. daydream <span class="pho alt">ˈdeɪ.driːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/daydream-us-male.mp3" data-audio-us-female="/audios/daydream-us-female.mp3"></span>
+13. dishwasher <span class="pho alt">ˈdɪʃˌwɑː.ʃɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/dishwasher-us-male.mp3" data-audio-us-female="/audios/dishwasher-us-female.mp3"></span>
+14. doorbell <span class="pho alt">ˈdɔːr.bel</span> <span class="speak-word-inline" data-audio-us-male="/audios/doorbell-us-male.mp3" data-audio-us-female="/audios/doorbell-us-female.mp3"></span>
+15. downtown <span class="pho alt">ˌdaʊnˈtaʊn</span> <span class="speak-word-inline" data-audio-us-male="/audios/downtown-us-male.mp3" data-audio-us-female="/audios/downtown-us-female.mp3"></span>
+16. earthquake <span class="pho alt">ˈɝːθ.kweɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/earthquake-us-male.mp3" data-audio-us-female="/audios/earthquake-us-female.mp3"></span>
+17. everyday <span class="pho alt">ˈev.ri.deɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/everyday-us-male.mp3" data-audio-us-female="/audios/everyday-us-female.mp3"></span>
+18. eyewitness <span class="pho alt">ˈaɪˌwɪt.nəs</span> <span class="speak-word-inline" data-audio-us-male="/audios/eyewitness-us-male.mp3" data-audio-us-female="/audios/eyewitness-us-female.mp3"></span>
+19. firefighter <span class="pho alt">ˈfaɪrˌfaɪ.t̬ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/firefighter-us-male.mp3" data-audio-us-female="/audios/firefighter-us-female.mp3"></span>
+20. football <span class="pho alt">ˈfʊt.bɑːl</span> <span class="speak-word-inline" data-audio-us-male="/audios/football-us-male.mp3" data-audio-us-female="/audios/football-us-female.mp3"></span>
+21. greenhouse <span class="pho alt">ˈɡriːn.haʊs</span> <span class="speak-word-inline" data-audio-us-male="/audios/greenhouse-us-male.mp3" data-audio-us-female="/audios/greenhouse-us-female.mp3"></span>
+22. handwriting <span class="pho alt">ˈhændˌraɪ.t̬ɪŋ</span> <span class="speak-word-inline" data-audio-us-male="/audios/handwriting-us-male.mp3" data-audio-us-female="/audios/handwriting-us-female.mp3"></span>
+23. headache <span class="pho alt">ˈhed.eɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/headache-us-male.mp3" data-audio-us-female="/audios/headache-us-female.mp3"></span>
+24. highway <span class="pho alt">ˈhaɪ.weɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/highway-us-male.mp3" data-audio-us-female="/audios/highway-us-female.mp3"></span>
+25. homework <span class="pho alt">ˈhoʊm.wɝːk</span> <span class="speak-word-inline" data-audio-us-male="/audios/homework-us-male.mp3" data-audio-us-female="/audios/homework-us-female.mp3"></span>
+26. iceberg <span class="pho alt">ˈaɪs.bɝːɡ</span> <span class="speak-word-inline" data-audio-us-male="/audios/iceberg-us-male.mp3" data-audio-us-female="/audios/iceberg-us-female.mp3"></span>
+27. jellyfish <span class="pho alt">ˈdʒel.i.fɪʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/jellyfish-us-male.mp3" data-audio-us-female="/audios/jellyfish-us-female.mp3"></span>
+28. laptop <span class="pho alt">ˈlæp.tɑːp</span> <span class="speak-word-inline" data-audio-us-male="/audios/laptop-us-male.mp3" data-audio-us-female="/audios/laptop-us-female.mp3"></span>
+29. lighthouse <span class="pho alt">ˈlaɪt.haʊs</span> <span class="speak-word-inline" data-audio-us-male="/audios/lighthouse-us-male.mp3" data-audio-us-female="/audios/lighthouse-us-female.mp3"></span>
+30. mailbox <span class="pho alt">ˈmeɪl.bɑːks</span> <span class="speak-word-inline" data-audio-us-male="/audios/mailbox-us-male.mp3" data-audio-us-female="/audios/mailbox-us-female.mp3"></span>
+31. moonlight <span class="pho alt">ˈmuːn.laɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/moonlight-us-male.mp3" data-audio-us-female="/audios/moonlight-us-female.mp3"></span>
+32. notebook <span class="pho alt">ˈnoʊt.bʊk</span> <span class="speak-word-inline" data-audio-us-male="/audios/notebook-us-male.mp3" data-audio-us-female="/audios/notebook-us-female.mp3"></span>
+33. nobody <span class="pho alt">ˈnoʊ.bɑː.di</span> <span class="speak-word-inline" data-audio-us-male="/audios/nobody-us-male.mp3" data-audio-us-female="/audios/nobody-us-female.mp3"></span>
+34. pancake <span class="pho alt">ˈpæn.keɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/pancake-us-male.mp3" data-audio-us-female="/audios/pancake-us-female.mp3"></span>
+35. postcard <span class="pho alt">ˈpoʊst.kɑːrd</span> <span class="speak-word-inline" data-audio-us-male="/audios/postcard-us-male.mp3" data-audio-us-female="/audios/postcard-us-female.mp3"></span>
+36. rainbow <span class="pho alt">ˈreɪn.boʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/rainbow-us-male.mp3" data-audio-us-female="/audios/rainbow-us-female.mp3"></span>
+37. sailboat <span class="pho alt">ˈseɪl.boʊt</span> <span class="speak-word-inline" data-audio-us-male="/audios/sailboat-us-male.mp3" data-audio-us-female="/audios/sailboat-us-female.mp3"></span>
+38. sandbox <span class="pho alt">ˈsænd.bɑːks</span> <span class="speak-word-inline" data-audio-us-male="/audios/sandbox-us-male.mp3" data-audio-us-female="/audios/sandbox-us-female.mp3"></span>
+39. seashore <span class="pho alt">ˈsiː.ʃɔːr</span> <span class="speak-word-inline" data-audio-us-male="/audios/seashore-us-male.mp3" data-audio-us-female="/audios/seashore-us-female.mp3"></span>
+40. skateboard <span class="pho alt">ˈskeɪt.bɔːrd</span> <span class="speak-word-inline" data-audio-us-male="/audios/skateboard-us-male.mp3" data-audio-us-female="/audios/skateboard-us-female.mp3"></span>
+41. snowflake <span class="pho alt">ˈsnoʊ.fleɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/snowflake-us-male.mp3" data-audio-us-female="/audios/snowflake-us-female.mp3"></span>
+42. spaceship <span class="pho alt">ˈspeɪs.ʃɪp</span> <span class="speak-word-inline" data-audio-us-male="/audios/spaceship-us-male.mp3" data-audio-us-female="/audios/spaceship-us-female.mp3"></span>
+43. sunflower <span class="pho alt">ˈsʌnˌflaʊ.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/sunflower-us-male.mp3" data-audio-us-female="/audios/sunflower-us-female.mp3"></span>
+44. sunshine <span class="pho alt">ˈsʌn.ʃaɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/sunshine-us-male.mp3" data-audio-us-female="/audios/sunshine-us-female.mp3"></span>
+45. superhero <span class="pho alt">ˈsuː.pɚˌhɪr.oʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/superhero-us-male.mp3" data-audio-us-female="/audios/superhero-us-female.mp3"></span>
+46. tablecloth <span class="pho alt">ˈteɪ.bəl.klɑːθ</span> <span class="speak-word-inline" data-audio-us-male="/audios/tablecloth-us-male.mp3" data-audio-us-female="/audios/tablecloth-us-female.mp3"></span>
+47. toothbrush <span class="pho alt">ˈtuːθ.brʌʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/toothbrush-us-male.mp3" data-audio-us-female="/audios/toothbrush-us-female.mp3"></span>
+48. toothpaste <span class="pho alt">ˈtuːθ.peɪst</span> <span class="speak-word-inline" data-audio-us-male="/audios/toothpaste-us-male.mp3" data-audio-us-female="/audios/toothpaste-us-female.mp3"></span>
+49. typewriter <span class="pho alt">ˈtaɪpˌraɪ.t̬ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/typewriter-us-male.mp3" data-audio-us-female="/audios/typewriter-us-female.mp3"></span>
+50. underwater <span class="pho alt">ˌʌn.dɚˈwɑː.t̬ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/underwater-us-male.mp3" data-audio-us-female="/audios/underwater-us-female.mp3"></span>
+51. upstairs <span class="pho alt">ʌpˈsterz</span> <span class="speak-word-inline" data-audio-us-male="/audios/upstairs-us-male.mp3" data-audio-us-female="/audios/upstairs-us-female.mp3"></span>
+52. volleyball <span class="pho alt">ˈvɑː.li.bɑːl</span> <span class="speak-word-inline" data-audio-us-male="/audios/volleyball-us-male.mp3" data-audio-us-female="/audios/volleyball-us-female.mp3"></span>
+53. waterfall <span class="pho alt">ˈwɑː.t̬ɚ.fɑːl</span> <span class="speak-word-inline" data-audio-us-male="/audios/waterfall-us-male.mp3" data-audio-us-female="/audios/waterfall-us-female.mp3"></span>
+54. watermelon <span class="pho alt">ˈwɑː.t̬ɚˌmel.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/watermelon-us-male.mp3" data-audio-us-female="/audios/watermelon-us-female.mp3"></span>
+55. weekend <span class="pho alt">ˈwiːk.end</span> <span class="speak-word-inline" data-audio-us-male="/audios/weekend-us-male.mp3" data-audio-us-female="/audios/weekend-us-female.mp3"></span>
+56. wheelchair <span class="pho alt">ˈwiːl.tʃer</span> <span class="speak-word-inline" data-audio-us-male="/audios/wheelchair-us-male.mp3" data-audio-us-female="/audios/wheelchair-us-female.mp3"></span>
+57. windmill <span class="pho alt">ˈwɪnd.mɪl</span> <span class="speak-word-inline" data-audio-us-male="/audios/windmill-us-male.mp3" data-audio-us-female="/audios/windmill-us-female.mp3"></span>
+58. workshop <span class="pho alt">ˈwɝːk.ʃɑːp</span> <span class="speak-word-inline" data-audio-us-male="/audios/workshop-us-male.mp3" data-audio-us-female="/audios/workshop-us-female.mp3"></span>
+
+</div>
+
+## 6.4. 常见词根词缀
+
+英文的词根大多来自拉丁语；而常用词缀，包括前缀和后缀 —— 它们都是表意的。
+
+### 6.4.1. 常见前缀
+
+<div class="two-column">
+
+1. **un-** (not, opposite of)
+  * unhappy <span class="pho alt">ʌnˈhæp.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/unhappy-us-male.mp3" data-audio-us-female="/audios/unhappy-us-female.mp3"></span>
+  * unknown <span class="pho alt">ʌnˈnoʊn</span> <span class="speak-word-inline" data-audio-us-male="/audios/unknown-us-male.mp3" data-audio-us-female="/audios/unknown-us-female.mp3"></span>
+  * unusual <span class="pho alt">ʌnˈjuː.ʒu.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/unusual-us-male.mp3" data-audio-us-female="/audios/unusual-us-female.mp3"></span>
+
+2. **re-** (again, back)
+  * redo <span class="pho alt">riːˈduː</span> <span class="speak-word-inline" data-audio-us-male="/audios/redo-us-male.mp3" data-audio-us-female="/audios/redo-us-female.mp3"></span>
+  * review <span class="pho alt">rɪˈvjuː</span> <span class="speak-word-inline" data-audio-us-male="/audios/review-us-male.mp3" data-audio-us-female="/audios/review-us-female.mp3"></span>
+  * return <span class="pho alt">rɪˈtɝːn</span> <span class="speak-word-inline" data-audio-us-male="/audios/return-us-male.mp3" data-audio-us-female="/audios/return-us-female.mp3"></span>
+
+3. **in-** (not, into)
+  * incomplete <span class="pho alt">ˌɪn.kəmˈpliːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/incomplete-us-male.mp3" data-audio-us-female="/audios/incomplete-us-female.mp3"></span>
+  * invisible <span class="pho alt">ɪnˈvɪz.ə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/invisible-us-male.mp3" data-audio-us-female="/audios/invisible-us-female.mp3"></span>
+  * inside <span class="pho alt">ɪnˈsaɪd</span> <span class="speak-word-inline" data-audio-us-male="/audios/inside-us-male.mp3" data-audio-us-female="/audios/inside-us-female.mp3"></span>
+
+4. **dis-** (not, opposite of)
+  * disagree <span class="pho alt">ˌdɪs.əˈɡriː</span> <span class="speak-word-inline" data-audio-us-male="/audios/disagree-us-male.mp3" data-audio-us-female="/audios/disagree-us-female.mp3"></span>
+  * disappear <span class="pho alt">ˌdɪs.əˈpɪr</span> <span class="speak-word-inline" data-audio-us-male="/audios/disappear-us-male.mp3" data-audio-us-female="/audios/disappear-us-female.mp3"></span>
+  * disconnect <span class="pho alt">ˌdɪs.kəˈnekt</span> <span class="speak-word-inline" data-audio-us-male="/audios/disconnect-us-male.mp3" data-audio-us-female="/audios/disconnect-us-female.mp3"></span>
+
+5. **pre-** (before)
+  * preview <span class="pho alt">ˈpriː.vjuː</span> <span class="speak-word-inline" data-audio-us-male="/audios/preview-us-male.mp3" data-audio-us-female="/audios/preview-us-female.mp3"></span>
+  * predict <span class="pho alt">prɪˈdɪkt</span> <span class="speak-word-inline" data-audio-us-male="/audios/predict-us-male.mp3" data-audio-us-female="/audios/predict-us-female.mp3"></span>
+  * preschool <span class="pho alt">ˈpriː.skuːl</span> <span class="speak-word-inline" data-audio-us-male="/audios/preschool-us-male.mp3" data-audio-us-female="/audios/preschool-us-female.mp3"></span>
+
+6. **mis-** (wrongly)
+  * misunderstand <span class="pho alt">ˌmɪs.ʌn.dɚˈstænd</span> <span class="speak-word-inline" data-audio-us-male="/audios/misunderstand-us-male.mp3" data-audio-us-female="/audios/misunderstand-us-female.mp3"></span>
+  * misplace <span class="pho alt">ˌmɪsˈpleɪs</span> <span class="speak-word-inline" data-audio-us-male="/audios/misplace-us-male.mp3" data-audio-us-female="/audios/misplace-us-female.mp3"></span>
+  * mislead <span class="pho alt">ˌmɪsˈliːd</span> <span class="speak-word-inline" data-audio-us-male="/audios/mislead-us-male.mp3" data-audio-us-female="/audios/mislead-us-female.mp3"></span>
+
+7. **non-** (not)
+  * nonstick <span class="pho alt">ˌnɑːnˈstɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/nonstick-us-male.mp3" data-audio-us-female="/audios/nonstick-us-female.mp3"></span>
+  * nonprofit <span class="pho alt">nɑnˈprɑf·ɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/nonprofit-us-male.mp3" data-audio-us-female="/audios/nonprofit-us-female.mp3"></span>
+  * nonviolent <span class="pho alt">ˌnɑːnˈvaɪə.lənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/nonviolent-us-male.mp3" data-audio-us-female="/audios/nonviolent-us-female.mp3"></span>
+
+8. **over-** (too much)
+  * overeat <span class="pho alt">ˌoʊ.vɚˈiːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/overeat-us-male.mp3" data-audio-us-female="/audios/overeat-us-female.mp3"></span>
+  * overwork <span class="pho alt">ˌoʊ.vɚˈwɝːk</span> <span class="speak-word-inline" data-audio-us-male="/audios/overwork-us-male.mp3" data-audio-us-female="/audios/overwork-us-female.mp3"></span>
+  * overheat <span class="pho alt">ˌoʊ.vɚˈhiːt</span> <span class="speak-word-inline" data-audio-us-male="/audios/overheat-us-male.mp3" data-audio-us-female="/audios/overheat-us-female.mp3"></span>
+
+9. **sub-** (under)
+  * submarine <span class="pho alt">ˌsʌb.məˈriːn</span> <span class="speak-word-inline" data-audio-us-male="/audios/submarine-us-male.mp3" data-audio-us-female="/audios/submarine-us-female.mp3"></span>
+  * subtitle <span class="pho alt">ˈsʌbˌtaɪ.t̬əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/subtitle-us-male.mp3" data-audio-us-female="/audios/subtitle-us-female.mp3"></span>
+  * subconscious <span class="pho alt">ˌsʌbˈkɑːn.ʃəs</span> <span class="speak-word-inline" data-audio-us-male="/audios/subconscious-us-male.mp3" data-audio-us-female="/audios/subconscious-us-female.mp3"></span>
+
+10. **inter-** (between, among)
+  * international <span class="pho alt">ˌɪn.t̬ɚˈnæʃ.ən.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/international-us-male.mp3" data-audio-us-female="/audios/international-us-female.mp3"></span>
+  * interact <span class="pho alt">ˌɪn.t̬ɚˈækt</span> <span class="speak-word-inline" data-audio-us-male="/audios/interact-us-male.mp3" data-audio-us-female="/audios/interact-us-female.mp3"></span>
+  * interrupt <span class="pho alt">ˌɪn.t̬əˈrʌpt</span> <span class="speak-word-inline" data-audio-us-male="/audios/interrupt-us-male.mp3" data-audio-us-female="/audios/interrupt-us-female.mp3"></span>
+
+11. **trans-** (across, beyond)
+  * transport <span class="pho alt">ˈtræn.spɔːrt</span> <span class="speak-word-inline" data-audio-us-male="/audios/transport-us-male.mp3" data-audio-us-female="/audios/transport-us-female.mp3"></span>
+  * transfer <span class="pho alt">ˈtræns.fɝː</span> <span class="speak-word-inline" data-audio-us-male="/audios/transfer-us-male.mp3" data-audio-us-female="/audios/transfer-us-female.mp3"></span>
+  * transform <span class="pho alt">trænsˈfɔːrm</span> <span class="speak-word-inline" data-audio-us-male="/audios/transform-us-male.mp3" data-audio-us-female="/audios/transform-us-female.mp3"></span>
+
+12. **under-** (too little, below)
+  * underpaid <span class="pho alt">ˌʌn.dɚˈpeɪd</span> <span class="speak-word-inline" data-audio-us-male="/audios/underpaid-us-male.mp3" data-audio-us-female="/audios/underpaid-us-female.mp3"></span>
+  * underestimate <span class="pho alt">ˌʌn.dɚˈes.tə.meɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/underestimate-us-male.mp3" data-audio-us-female="/audios/underestimate-us-female.mp3"></span>
+  * underground <span class="pho alt">ˌʌn.dɚˈɡraʊnd</span> <span class="speak-word-inline" data-audio-us-male="/audios/underground-us-male.mp3" data-audio-us-female="/audios/underground-us-female.mp3"></span>
+
+13. **super-** (above, beyond)
+  * superhuman <span class="pho alt">ˌsuː.pɚˈhjuː.mən</span> <span class="speak-word-inline" data-audio-us-male="/audios/superhuman-us-male.mp3" data-audio-us-female="/audios/superhuman-us-female.mp3"></span>
+  * supermarket <span class="pho alt">ˈsuː.pɚˌmɑːr.kɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/supermarket-us-male.mp3" data-audio-us-female="/audios/supermarket-us-female.mp3"></span>
+  * supervisor <span class="pho alt">ˈsuː.pɚ.vaɪ.zɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/supervisor-us-male.mp3" data-audio-us-female="/audios/supervisor-us-female.mp3"></span>
+
+14. **semi-** (half, partly)
+  * semicircle <span class="pho alt">ˈsem.iˌsɝː.kəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/semicircle-us-male.mp3" data-audio-us-female="/audios/semicircle-us-female.mp3"></span>
+  * semifinal <span class="pho alt">ˌsem.iˈfaɪ.nəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/semifinal-us-male.mp3" data-audio-us-female="/audios/semifinal-us-female.mp3"></span>
+  * semiconscious <span class="pho alt">ˌsem.aɪ.ˈkɑːn.ʃəs/</span> <span class="speak-word-inline" data-audio-us-male="/audios/semiconscious-us-male.mp3" data-audio-us-female="/audios/semiconscious-us-female.mp3"></span>
+
+15. **anti-** (against)
+  * antibiotic <span class="pho alt">ˌæn.t̬i.baɪˈɑː.t̬ɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/antibiotic-us-male.mp3" data-audio-us-female="/audios/antibiotic-us-female.mp3"></span>
+  * antifreeze <span class="pho alt">ˈæn.t̬i.friːz</span> <span class="speak-word-inline" data-audio-us-male="/audios/antifreeze-us-male.mp3" data-audio-us-female="/audios/antifreeze-us-female.mp3"></span>
+  * antisocial <span class="pho alt">ˌæn.t̬iˈsoʊ.ʃəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/antisocial-us-male.mp3" data-audio-us-female="/audios/antisocial-us-female.mp3"></span>
+
+16. **de-** (down, away from)
+  * devalue <span class="pho alt">ˌdiːˈvæl.juː</span> <span class="speak-word-inline" data-audio-us-male="/audios/devalue-us-male.mp3" data-audio-us-female="/audios/devalue-us-female.mp3"></span>
+  * defrost <span class="pho alt">ˌdiːˈfrɑːst</span> <span class="speak-word-inline" data-audio-us-male="/audios/defrost-us-male.mp3" data-audio-us-female="/audios/defrost-us-female.mp3"></span>
+  * decode <span class="pho alt">diːˈkoʊd</span> <span class="speak-word-inline" data-audio-us-male="/audios/decode-us-male.mp3" data-audio-us-female="/audios/decode-us-female.mp3"></span>
+
+17. **en-** (make, put into)
+  * enable <span class="pho alt">ɪˈneɪ.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/enable-us-male.mp3" data-audio-us-female="/audios/enable-us-female.mp3"></span>
+  * enrich <span class="pho alt">ɪnˈrɪtʃ</span> <span class="speak-word-inline" data-audio-us-male="/audios/enrich-us-male.mp3" data-audio-us-female="/audios/enrich-us-female.mp3"></span>
+  * encourage <span class="pho alt">ɪnˈkɝː.ɪdʒ</span> <span class="speak-word-inline" data-audio-us-male="/audios/encourage-us-male.mp3" data-audio-us-female="/audios/encourage-us-female.mp3"></span>
+
+18. **em-** (cause to)
+  * empower <span class="pho alt">-ˈpaʊr</span> <span class="speak-word-inline" data-audio-us-male="/audios/empower-us-male.mp3" data-audio-us-female="/audios/empower-us-female.mp3"></span>
+  * embrace <span class="pho alt">ɪmˈbreɪs</span> <span class="speak-word-inline" data-audio-us-male="/audios/embrace-us-male.mp3" data-audio-us-female="/audios/embrace-us-female.mp3"></span>
+  * employ <span class="pho alt">ɪmˈplɔɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/employ-us-male.mp3" data-audio-us-female="/audios/employ-us-female.mp3"></span>
+
+19. **non-** (not)
+  * nonexistent <span class="pho alt">ˌnɑn·ɪɡˈzɪs·tənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/nonexistent-us-male.mp3" data-audio-us-female="/audios/nonexistent-us-female.mp3"></span>
+  * nonsense <span class="pho alt">ˈnɑːn.sens</span> <span class="speak-word-inline" data-audio-us-male="/audios/nonsense-us-male.mp3" data-audio-us-female="/audios/nonsense-us-female.mp3"></span>
+  * nonprofit <span class="pho alt">nɑnˈprɑf·ɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/nonprofit-us-male.mp3" data-audio-us-female="/audios/nonprofit-us-female.mp3"></span>
+
+20. **mid-** (middle)
+  * midnight <span class="pho alt">ˈmɪd.naɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/midnight-us-male.mp3" data-audio-us-female="/audios/midnight-us-female.mp3"></span>
+  * midterm <span class="pho alt">ˈmɪd.tɝːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/midterm-us-male.mp3" data-audio-us-female="/audios/midterm-us-female.mp3"></span>
+  * midfield <span class="pho alt">ˈmɪd.fiːld</span> <span class="speak-word-inline" data-audio-us-male="/audios/midfield-us-male.mp3" data-audio-us-female="/audios/midfield-us-female.mp3"></span>
+
+### 6.4.2. 常见后缀
+
+1. **-able** (capable of)
+  * readable <span class="pho alt">ˈriː.də.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/readable-us-male.mp3" data-audio-us-female="/audios/readable-us-female.mp3"></span>
+  * manageable <span class="pho alt">ˈmæn.ə.dʒə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/manageable-us-male.mp3" data-audio-us-female="/audios/manageable-us-female.mp3"></span>
+  * comfortable <span class="pho alt">ˈkʌm.fɚ.t̬ə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/comfortable-us-male.mp3" data-audio-us-female="/audios/comfortable-us-female.mp3"></span>
+
+2. **-ible** (capable of)
+  * visible <span class="pho alt">ˈvɪz.ə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/visible-us-male.mp3" data-audio-us-female="/audios/visible-us-female.mp3"></span>
+  * flexible <span class="pho alt">ˈflek.sə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/flexible-us-male.mp3" data-audio-us-female="/audios/flexible-us-female.mp3"></span>
+  * edible <span class="pho alt">ˈed.ə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/edible-us-male.mp3" data-audio-us-female="/audios/edible-us-female.mp3"></span>
+
+3. **-al** (relating to)
+  * natural <span class="pho alt">ˈnætʃ.ɚ.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/natural-us-male.mp3" data-audio-us-female="/audios/natural-us-female.mp3"></span>
+  * musical <span class="pho alt">ˈmjuː.zɪ.kəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/musical-us-male.mp3" data-audio-us-female="/audios/musical-us-female.mp3"></span>
+  * personal <span class="pho alt">ˈpɝː.sən.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/personal-us-male.mp3" data-audio-us-female="/audios/personal-us-female.mp3"></span>
+
+4. **-ful** (full of)
+  * helpful <span class="pho alt">ˈhelp.fəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/helpful-us-male.mp3" data-audio-us-female="/audios/helpful-us-female.mp3"></span>
+  * joyful <span class="pho alt">ˈdʒɔɪ.fəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/joyful-us-male.mp3" data-audio-us-female="/audios/joyful-us-female.mp3"></span>
+  * careful <span class="pho alt">ˈker.fəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/careful-us-male.mp3" data-audio-us-female="/audios/careful-us-female.mp3"></span>
+
+5. **-less** (without)
+  * hopeless <span class="pho alt">ˈhoʊp.ləs</span> <span class="speak-word-inline" data-audio-us-male="/audios/hopeless-us-male.mp3" data-audio-us-female="/audios/hopeless-us-female.mp3"></span>
+  * fearless <span class="pho alt">ˈfɪr.ləs</span> <span class="speak-word-inline" data-audio-us-male="/audios/fearless-us-male.mp3" data-audio-us-female="/audios/fearless-us-female.mp3"></span>
+  * endless <span class="pho alt">ˈend.ləs</span> <span class="speak-word-inline" data-audio-us-male="/audios/endless-us-male.mp3" data-audio-us-female="/audios/endless-us-female.mp3"></span>
+
+6. **-ly** (in the manner of)
+  * quickly <span class="pho alt">ˈkwɪk.li</span> <span class="speak-word-inline" data-audio-us-male="/audios/quickly-us-male.mp3" data-audio-us-female="/audios/quickly-us-female.mp3"></span>
+  * slowly <span class="pho alt">ˈsloʊ.li</span> <span class="speak-word-inline" data-audio-us-male="/audios/slowly-us-male.mp3" data-audio-us-female="/audios/slowly-us-female.mp3"></span>
+  * happily <span class="pho alt">ˈhæp.əl.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/happily-us-male.mp3" data-audio-us-female="/audios/happily-us-female.mp3"></span>
+
+7. **-ment** (action or process)
+  * development <span class="pho alt">dɪˈvel.əp.mənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/development-us-male.mp3" data-audio-us-female="/audios/development-us-female.mp3"></span>
+  * agreement <span class="pho alt">əˈɡriː.mənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/agreement-us-male.mp3" data-audio-us-female="/audios/agreement-us-female.mp3"></span>
+  * improvement <span class="pho alt">ɪmˈpruːv.mənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/improvement-us-male.mp3" data-audio-us-female="/audios/improvement-us-female.mp3"></span>
+
+8. **-ness** (state or quality)
+  * kindness <span class="pho alt">ˈkaɪnd.nəs</span> <span class="speak-word-inline" data-audio-us-male="/audios/kindness-us-male.mp3" data-audio-us-female="/audios/kindness-us-female.mp3"></span>
+  * darkness <span class="pho alt">ˈdɑːrk.nəs</span> <span class="speak-word-inline" data-audio-us-male="/audios/darkness-us-male.mp3" data-audio-us-female="/audios/darkness-us-female.mp3"></span>
+  * happiness <span class="pho alt">ˈhæp.i.nəs</span> <span class="speak-word-inline" data-audio-us-male="/audios/happiness-us-male.mp3" data-audio-us-female="/audios/happiness-us-female.mp3"></span>
+
+9. **-er** (one who, comparative)
+  * teacher <span class="pho alt">ˈtiː.tʃɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/teacher-us-male.mp3" data-audio-us-female="/audios/teacher-us-female.mp3"></span>
+  * runner <span class="pho alt">ˈrʌn.ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/runner-us-male.mp3" data-audio-us-female="/audios/runner-us-female.mp3"></span>
+  * faster <span class="pho alt">fæst</span> <span class="speak-word-inline" data-audio-us-male="/audios/faster-us-male.mp3" data-audio-us-female="/audios/faster-us-female.mp3"></span>
+
+10. **-or** (one who)
+  * actor <span class="pho alt">ˈæk.tɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/actor-us-male.mp3" data-audio-us-female="/audios/actor-us-female.mp3"></span>
+  * inventor <span class="pho alt">ɪnˈven.t̬ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/inventor-us-male.mp3" data-audio-us-female="/audios/inventor-us-female.mp3"></span>
+  * conductor <span class="pho alt">kənˈdʌk.tɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/conductor-us-male.mp3" data-audio-us-female="/audios/conductor-us-female.mp3"></span>
+
+11. **-ist** (one who practices)
+  * artist <span class="pho alt">ˈɑːr.t̬ɪst</span> <span class="speak-word-inline" data-audio-us-male="/audios/artist-us-male.mp3" data-audio-us-female="/audios/artist-us-female.mp3"></span>
+  * scientist <span class="pho alt">ˈsaɪən.tɪst</span> <span class="speak-word-inline" data-audio-us-male="/audios/scientist-us-male.mp3" data-audio-us-female="/audios/scientist-us-female.mp3"></span>
+  * pianist <span class="pho alt">ˈpiː.ən.ɪst</span> <span class="speak-word-inline" data-audio-us-male="/audios/pianist-us-male.mp3" data-audio-us-female="/audios/pianist-us-female.mp3"></span>
+
+12. **-ion** (action or condition)
+  * celebration <span class="pho alt">ˌsel.əˈbreɪ.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/celebration-us-male.mp3" data-audio-us-female="/audios/celebration-us-female.mp3"></span>
+  * decision <span class="pho alt">dɪˈsɪʒ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/decision-us-male.mp3" data-audio-us-female="/audios/decision-us-female.mp3"></span>
+  * creation <span class="pho alt">kriˈeɪ.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/creation-us-male.mp3" data-audio-us-female="/audios/creation-us-female.mp3"></span>
+
+13. **-tion** (action or condition)
+  * education <span class="pho alt">ˌedʒ.əˈkeɪ.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/education-us-male.mp3" data-audio-us-female="/audios/education-us-female.mp3"></span>
+  * suggestion <span class="pho alt">səˈdʒes.tʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/suggestion-us-male.mp3" data-audio-us-female="/audios/suggestion-us-female.mp3"></span>
+  * transportation <span class="pho alt">ˌtræn.spɚˈteɪ.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/transportation-us-male.mp3" data-audio-us-female="/audios/transportation-us-female.mp3"></span>
+
+14. **-sion** (state or condition)
+  * admission <span class="pho alt">ədˈmɪʃ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/admission-us-male.mp3" data-audio-us-female="/audios/admission-us-female.mp3"></span>
+  * confusion <span class="pho alt">kənˈfjuː.ʒən</span> <span class="speak-word-inline" data-audio-us-male="/audios/confusion-us-male.mp3" data-audio-us-female="/audios/confusion-us-female.mp3"></span>
+  * extension <span class="pho alt">ɪkˈsten.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/extension-us-male.mp3" data-audio-us-female="/audios/extension-us-female.mp3"></span>
+
+15. **-ous** (full of)
+  * dangerous <span class="pho alt">ˈdeɪn.dʒɚ.əs</span> <span class="speak-word-inline" data-audio-us-male="/audios/dangerous-us-male.mp3" data-audio-us-female="/audios/dangerous-us-female.mp3"></span>
+  * nervous <span class="pho alt">ˈnɝː.vəs</span> <span class="speak-word-inline" data-audio-us-male="/audios/nervous-us-male.mp3" data-audio-us-female="/audios/nervous-us-female.mp3"></span>
+  * famous <span class="pho alt">ˈfeɪ.məs</span> <span class="speak-word-inline" data-audio-us-male="/audios/famous-us-male.mp3" data-audio-us-female="/audios/famous-us-female.mp3"></span>
+
+16. **-ive** (tending to)
+  * active <span class="pho alt">ˈæk.tɪv</span> <span class="speak-word-inline" data-audio-us-male="/audios/active-us-male.mp3" data-audio-us-female="/audios/active-us-female.mp3"></span>
+  * creative <span class="pho alt">kriˈeɪ.t̬ɪv</span> <span class="speak-word-inline" data-audio-us-male="/audios/creative-us-male.mp3" data-audio-us-female="/audios/creative-us-female.mp3"></span>
+  * attractive <span class="pho alt">əˈtræk.tɪv</span> <span class="speak-word-inline" data-audio-us-male="/audios/attractive-us-male.mp3" data-audio-us-female="/audios/attractive-us-female.mp3"></span>
+
+17. **-ic** (relating to)
+  * artistic <span class="pho alt">ɑːrˈtɪs.tɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/artistic-us-male.mp3" data-audio-us-female="/audios/artistic-us-female.mp3"></span>
+  * athletic <span class="pho alt">æθˈlet̬.ɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/athletic-us-male.mp3" data-audio-us-female="/audios/athletic-us-female.mp3"></span>
+  * energetic <span class="pho alt">ˌen.ɚˈdʒet̬.ɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/energetic-us-male.mp3" data-audio-us-female="/audios/energetic-us-female.mp3"></span>
+
+18. **-ity** (state or quality)
+  * reality <span class="pho alt">riˈæl.ə.t̬i</span> <span class="speak-word-inline" data-audio-us-male="/audios/reality-us-male.mp3" data-audio-us-female="/audios/reality-us-female.mp3"></span>
+  * ability <span class="pho alt">əˈbɪl.ə.t̬i</span> <span class="speak-word-inline" data-audio-us-male="/audios/ability-us-male.mp3" data-audio-us-female="/audios/ability-us-female.mp3"></span>
+  * simplicity <span class="pho alt">sɪmˈplɪs.ə.t̬i</span> <span class="speak-word-inline" data-audio-us-male="/audios/simplicity-us-male.mp3" data-audio-us-female="/audios/simplicity-us-female.mp3"></span>
+
+19. **-ance** (state or quality)
+  * performance <span class="pho alt">pɚˈfɔːr.məns</span> <span class="speak-word-inline" data-audio-us-male="/audios/performance-us-male.mp3" data-audio-us-female="/audios/performance-us-female.mp3"></span>
+  * importance <span class="pho alt">ɪmˈpɔːr.təns</span> <span class="speak-word-inline" data-audio-us-male="/audios/importance-us-male.mp3" data-audio-us-female="/audios/importance-us-female.mp3"></span>
+  * acceptance <span class="pho alt">əkˈsep.təns</span> <span class="speak-word-inline" data-audio-us-male="/audios/acceptance-us-male.mp3" data-audio-us-female="/audios/acceptance-us-female.mp3"></span>
+
+20. **-ence** (state or quality)
+  * difference <span class="pho alt">ˈdɪf.ɚ.əns</span> <span class="speak-word-inline" data-audio-us-male="/audios/difference-us-male.mp3" data-audio-us-female="/audios/difference-us-female.mp3"></span>
+  * independence <span class="pho alt">ˌɪn.dɪˈpen.dəns</span> <span class="speak-word-inline" data-audio-us-male="/audios/independence-us-male.mp3" data-audio-us-female="/audios/independence-us-female.mp3"></span>
+  * existence <span class="pho alt">ɪɡˈzɪs.təns</span> <span class="speak-word-inline" data-audio-us-male="/audios/existence-us-male.mp3" data-audio-us-female="/audios/existence-us-female.mp3"></span>
+
+</div>
+
+### 6.4.3. 常见词根
+
+<div class="two-column">
+
+1. **aqua** (water)
+  * aquarium <span class="pho alt">əˈkwer.i.əm</span> <span class="speak-word-inline" data-audio-us-male="/audios/aquarium-us-male.mp3" data-audio-us-female="/audios/aquarium-us-female.mp3"></span>
+  * aquatic <span class="pho alt">əˈkwæt̬.ɪk</span> <span class="speak-word-inline" data-audio-us-male="/audios/aquatic-us-male.mp3" data-audio-us-female="/audios/aquatic-us-female.mp3"></span>
+  * aqueduct <span class="pho alt">ˈæk.wə.dʌkt</span> <span class="speak-word-inline" data-audio-us-male="/audios/aqueduct-us-male.mp3" data-audio-us-female="/audios/aqueduct-us-female.mp3"></span>
+
+2. **aud** (hear)
+  * audience <span class="pho alt">ˈɑː.di.əns</span> <span class="speak-word-inline" data-audio-us-male="/audios/audience-us-male.mp3" data-audio-us-female="/audios/audience-us-female.mp3"></span>
+  * audio <span class="pho alt">ˈɑː.di.oʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/audio-us-male.mp3" data-audio-us-female="/audios/audio-us-female.mp3"></span>
+  * audition <span class="pho alt">ɑːˈdɪʃ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/audition-us-male.mp3" data-audio-us-female="/audios/audition-us-female.mp3"></span>
+
+3. **bene** (good, well)
+  * benefit <span class="pho alt">ˈben.ə.fɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/benefit-us-male.mp3" data-audio-us-female="/audios/benefit-us-female.mp3"></span>
+  * benevolent <span class="pho alt">bəˈnev.əl.ənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/benevolent-us-male.mp3" data-audio-us-female="/audios/benevolent-us-female.mp3"></span>
+  * benefactor <span class="pho alt">ˈben.ə.fæk.tɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/benefactor-us-male.mp3" data-audio-us-female="/audios/benefactor-us-female.mp3"></span>
+
+4. **cent** (hundred)
+  * century <span class="pho alt">ˈsen.tʃər.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/century-us-male.mp3" data-audio-us-female="/audios/century-us-female.mp3"></span>
+  * percent <span class="pho alt">pɚˈsent</span> <span class="speak-word-inline" data-audio-us-male="/audios/percent-us-male.mp3" data-audio-us-female="/audios/percent-us-female.mp3"></span>
+  * centennial <span class="pho alt">senˈten.i.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/centennial-us-male.mp3" data-audio-us-female="/audios/centennial-us-female.mp3"></span>
+
+5. **dict** (say, speak)
+  * dictionary <span class="pho alt">ˈdɪk.ʃən.er.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/dictionary-us-male.mp3" data-audio-us-female="/audios/dictionary-us-female.mp3"></span>
+  * predict <span class="pho alt">prɪˈdɪkt</span> <span class="speak-word-inline" data-audio-us-male="/audios/predict-us-male.mp3" data-audio-us-female="/audios/predict-us-female.mp3"></span>
+  * dictate <span class="pho alt">ˈdɪk.teɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/dictate-us-male.mp3" data-audio-us-female="/audios/dictate-us-female.mp3"></span>
+
+6. **duc** (lead)
+  * conduct <span class="pho alt">kənˈdʌkt</span> <span class="speak-word-inline" data-audio-us-male="/audios/conduct-us-male.mp3" data-audio-us-female="/audios/conduct-us-female.mp3"></span>
+  * produce <span class="pho alt">prəˈduːs</span> <span class="speak-word-inline" data-audio-us-male="/audios/produce-us-male.mp3" data-audio-us-female="/audios/produce-us-female.mp3"></span>
+  * reduce <span class="pho alt">rɪˈduːs</span> <span class="speak-word-inline" data-audio-us-male="/audios/reduce-us-male.mp3" data-audio-us-female="/audios/reduce-us-female.mp3"></span>
+
+7. **fract** (break)
+  * fracture <span class="pho alt">ˈfræk.tʃɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/fracture-us-male.mp3" data-audio-us-female="/audios/fracture-us-female.mp3"></span>
+  * fraction <span class="pho alt">ˈfræk.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/fraction-us-male.mp3" data-audio-us-female="/audios/fraction-us-female.mp3"></span>
+  * infraction <span class="pho alt">ɪnˈfræk.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/infraction-us-male.mp3" data-audio-us-female="/audios/infraction-us-female.mp3"></span>
+
+8. **ject** (throw)
+  * project <span class="pho alt">ˈprɑː.dʒekt</span> <span class="speak-word-inline" data-audio-us-male="/audios/project-us-male.mp3" data-audio-us-female="/audios/project-us-female.mp3"></span>
+  * inject <span class="pho alt">ɪnˈdʒekt</span> <span class="speak-word-inline" data-audio-us-male="/audios/inject-us-male.mp3" data-audio-us-female="/audios/inject-us-female.mp3"></span>
+  * reject <span class="pho alt">rɪˈdʒekt</span> <span class="speak-word-inline" data-audio-us-male="/audios/reject-us-male.mp3" data-audio-us-female="/audios/reject-us-female.mp3"></span>
+
+9. **jud** (judge)
+  * judicial <span class="pho alt">dʒuːˈdɪʃ.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/judicial-us-male.mp3" data-audio-us-female="/audios/judicial-us-female.mp3"></span>
+  * prejudice <span class="pho alt">ˈpredʒ.ə.dɪs</span> <span class="speak-word-inline" data-audio-us-male="/audios/prejudice-us-male.mp3" data-audio-us-female="/audios/prejudice-us-female.mp3"></span>
+  * judgment <span class="pho alt">ˈdʒʌdʒ.mənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/judgment-us-male.mp3" data-audio-us-female="/audios/judgment-us-female.mp3"></span>
+
+10. **mal** (bad, ill)
+  * malnutrition <span class="pho alt">ˌmæl.nuːˈtrɪʃ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/malnutrition-us-male.mp3" data-audio-us-female="/audios/malnutrition-us-female.mp3"></span>
+  * malicious <span class="pho alt">məˈlɪʃ.əs</span> <span class="speak-word-inline" data-audio-us-male="/audios/malicious-us-male.mp3" data-audio-us-female="/audios/malicious-us-female.mp3"></span>
+  * malfunction <span class="pho alt">ˌmælˈfʌŋk.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/malfunction-us-male.mp3" data-audio-us-female="/audios/malfunction-us-female.mp3"></span>
+
+11. **mater** (mother)
+  * maternal <span class="pho alt">məˈtɝː.nəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/maternal-us-male.mp3" data-audio-us-female="/audios/maternal-us-female.mp3"></span>
+  * maternity <span class="pho alt">məˈtɝː.nə.t̬i</span> <span class="speak-word-inline" data-audio-us-male="/audios/maternity-us-male.mp3" data-audio-us-female="/audios/maternity-us-female.mp3"></span>
+  * matriarch <span class="pho alt">ˈmeɪ.tri.ɑːrk</span> <span class="speak-word-inline" data-audio-us-male="/audios/matriarch-us-male.mp3" data-audio-us-female="/audios/matriarch-us-female.mp3"></span>
+
+12. **mit** (send)
+  * transmit <span class="pho alt">trænsˈmɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/transmit-us-male.mp3" data-audio-us-female="/audios/transmit-us-female.mp3"></span>
+  * admit <span class="pho alt">ədˈmɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/admit-us-male.mp3" data-audio-us-female="/audios/admit-us-female.mp3"></span>
+  * submit <span class="pho alt">səbˈmɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/submit-us-male.mp3" data-audio-us-female="/audios/submit-us-female.mp3"></span>
+
+13. **mort** (death)
+  * mortal <span class="pho alt">ˈmɔːr.t̬əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/mortal-us-male.mp3" data-audio-us-female="/audios/mortal-us-female.mp3"></span>
+  * mortician <span class="pho alt">mɔːrˈtɪʃ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/mortician-us-male.mp3" data-audio-us-female="/audios/mortician-us-female.mp3"></span>
+  * mortify <span class="pho alt">ˈmɔːr.t̬ə.faɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/mortify-us-male.mp3" data-audio-us-female="/audios/mortify-us-female.mp3"></span>
+
+14. **multi** (many)
+  * multiple <span class="pho alt">ˈmʌl.tə.pəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/multiple-us-male.mp3" data-audio-us-female="/audios/multiple-us-female.mp3"></span>
+  * multiply <span class="pho alt">ˈmʌl.tə.plaɪ</span> <span class="speak-word-inline" data-audio-us-male="/audios/multiply-us-male.mp3" data-audio-us-female="/audios/multiply-us-female.mp3"></span>
+  * multinational <span class="pho alt">ˌmʌl.t̬iˈnæʃ.ən.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/multinational-us-male.mp3" data-audio-us-female="/audios/multinational-us-female.mp3"></span>
+
+15. **pend** (hang, weigh)
+  * pendant <span class="pho alt">ˈpen.dənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/pendant-us-male.mp3" data-audio-us-female="/audios/pendant-us-female.mp3"></span>
+  * suspend <span class="pho alt">səˈspend</span> <span class="speak-word-inline" data-audio-us-male="/audios/suspend-us-male.mp3" data-audio-us-female="/audios/suspend-us-female.mp3"></span>
+  * depend <span class="pho alt">dɪˈpend</span> <span class="speak-word-inline" data-audio-us-male="/audios/depend-us-male.mp3" data-audio-us-female="/audios/depend-us-female.mp3"></span>
+
+16. **port** (carry)
+  * transport <span class="pho alt">ˈtræn.spɔːrt</span> <span class="speak-word-inline" data-audio-us-male="/audios/transport-us-male.mp3" data-audio-us-female="/audios/transport-us-female.mp3"></span>
+  * export <span class="pho alt">ˈek.spɔːrt</span> <span class="speak-word-inline" data-audio-us-male="/audios/export-us-male.mp3" data-audio-us-female="/audios/export-us-female.mp3"></span>
+  * import <span class="pho alt">ˈɪm.pɔːrt</span> <span class="speak-word-inline" data-audio-us-male="/audios/import-us-male.mp3" data-audio-us-female="/audios/import-us-female.mp3"></span>
+
+17. **scrib/script** (write)
+  * describe <span class="pho alt">dɪˈskraɪb</span> <span class="speak-word-inline" data-audio-us-male="/audios/describe-us-male.mp3" data-audio-us-female="/audios/describe-us-female.mp3"></span>
+  * manuscript <span class="pho alt">ˈmæn.jə.skrɪpt</span> <span class="speak-word-inline" data-audio-us-male="/audios/manuscript-us-male.mp3" data-audio-us-female="/audios/manuscript-us-female.mp3"></span>
+  * subscription <span class="pho alt">səbˈskrɪp.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/subscription-us-male.mp3" data-audio-us-female="/audios/subscription-us-female.mp3"></span>
+
+18. **sect/sec** (cut)
+  * section <span class="pho alt">ˈsek.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/section-us-male.mp3" data-audio-us-female="/audios/section-us-female.mp3"></span>
+  * dissect <span class="pho alt">daɪˈsekt</span> <span class="speak-word-inline" data-audio-us-male="/audios/dissect-us-male.mp3" data-audio-us-female="/audios/dissect-us-female.mp3"></span>
+  * intersect <span class="pho alt">ˌɪn.t̬ɚˈsekt</span> <span class="speak-word-inline" data-audio-us-male="/audios/intersect-us-male.mp3" data-audio-us-female="/audios/intersect-us-female.mp3"></span>
+
+19. **sent/sens** (feel)
+  * sensation <span class="pho alt">senˈseɪ.ʃən</span> <span class="speak-word-inline" data-audio-us-male="/audios/sensation-us-male.mp3" data-audio-us-female="/audios/sensation-us-female.mp3"></span>
+  * sensitive <span class="pho alt">ˈsen.sə.t̬ɪv</span> <span class="speak-word-inline" data-audio-us-male="/audios/sensitive-us-male.mp3" data-audio-us-female="/audios/sensitive-us-female.mp3"></span>
+  * consent <span class="pho alt">kənˈsent</span> <span class="speak-word-inline" data-audio-us-male="/audios/consent-us-male.mp3" data-audio-us-female="/audios/consent-us-female.mp3"></span>
+
+20. **spec/spect** (look)
+  * inspect <span class="pho alt">ɪnˈspekt</span> <span class="speak-word-inline" data-audio-us-male="/audios/inspect-us-male.mp3" data-audio-us-female="/audios/inspect-us-female.mp3"></span>
+  * spectator <span class="pho alt">spekˈteɪ.t̬ɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/spectator-us-male.mp3" data-audio-us-female="/audios/spectator-us-female.mp3"></span>
+  * spectacle <span class="pho alt">ˈspek.tə.kəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/spectacle-us-male.mp3" data-audio-us-female="/audios/spectacle-us-female.mp3"></span>
+
+21. **struct** (build)
+  * construct <span class="pho alt">kənˈstrʌkt</span> <span class="speak-word-inline" data-audio-us-male="/audios/construct-us-male.mp3" data-audio-us-female="/audios/construct-us-female.mp3"></span>
+  * structure <span class="pho alt">ˈstrʌk.tʃɚ</span> <span class="speak-word-inline" data-audio-us-male="/audios/structure-us-male.mp3" data-audio-us-female="/audios/structure-us-female.mp3"></span>
+  * destruct <span class="pho alt">ˌself.dɪˈstrʌkt</span> <span class="speak-word-inline" data-audio-us-male="/audios/destruct-us-male.mp3" data-audio-us-female="/audios/destruct-us-female.mp3"></span>
+
+22. **tele** (far)
+  * telephone <span class="pho alt">ˈtel.ə.foʊn</span> <span class="speak-word-inline" data-audio-us-male="/audios/telephone-us-male.mp3" data-audio-us-female="/audios/telephone-us-female.mp3"></span>
+  * television <span class="pho alt">ˈtel.ə.vɪʒ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/television-us-male.mp3" data-audio-us-female="/audios/television-us-female.mp3"></span>
+  * telegraph <span class="pho alt">ˈtel.ə.ɡræf</span> <span class="speak-word-inline" data-audio-us-male="/audios/telegraph-us-male.mp3" data-audio-us-female="/audios/telegraph-us-female.mp3"></span>
+
+23. **terra** (earth)
+  * terrestrial <span class="pho alt">təˈres.tri.əl</span> <span class="speak-word-inline" data-audio-us-male="/audios/terrestrial-us-male.mp3" data-audio-us-female="/audios/terrestrial-us-female.mp3"></span>
+  * territory <span class="pho alt">ˈter.ə.tɔːr.i</span> <span class="speak-word-inline" data-audio-us-male="/audios/territory-us-male.mp3" data-audio-us-female="/audios/territory-us-female.mp3"></span>
+  * terrain <span class="pho alt">təˈreɪn</span> <span class="speak-word-inline" data-audio-us-male="/audios/terrain-us-male.mp3" data-audio-us-female="/audios/terrain-us-female.mp3"></span>
+
+24. **vac** (empty)
+  * vacant <span class="pho alt">ˈveɪ.kənt</span> <span class="speak-word-inline" data-audio-us-male="/audios/vacant-us-male.mp3" data-audio-us-female="/audios/vacant-us-female.mp3"></span>
+  * vacuum <span class="pho alt">ˈvæk.juːm</span> <span class="speak-word-inline" data-audio-us-male="/audios/vacuum-us-male.mp3" data-audio-us-female="/audios/vacuum-us-female.mp3"></span>
+  * evacuate <span class="pho alt">ɪˈvæk.ju.eɪt</span> <span class="speak-word-inline" data-audio-us-male="/audios/evacuate-us-male.mp3" data-audio-us-female="/audios/evacuate-us-female.mp3"></span>
+
+25. **vid/vis** (see)
+  * video <span class="pho alt">ˈvɪd.i.oʊ</span> <span class="speak-word-inline" data-audio-us-male="/audios/video-us-male.mp3" data-audio-us-female="/audios/video-us-female.mp3"></span>
+  * vision <span class="pho alt">ˈvɪʒ.ən</span> <span class="speak-word-inline" data-audio-us-male="/audios/vision-us-male.mp3" data-audio-us-female="/audios/vision-us-female.mp3"></span>
+  * invisible <span class="pho alt">ɪnˈvɪz.ə.bəl</span> <span class="speak-word-inline" data-audio-us-male="/audios/invisible-us-male.mp3" data-audio-us-female="/audios/invisible-us-female.mp3"></span>
+
+</div>
+
+<style>
+    .two-column ol, .two-column ul {
+        column-count: 2 !important;
+        column-gap: 2em;
+    }
+</style>
+